Magnetism And Matter Questions

We provide magnetism and matter practice exercises, instructions, and a learning material that allows learners to study outside of the classroom. We focus on magnetism and matter skills mastery so, below you will get all questions that are also asking in the competition exam beside that classroom.

Magnetism And Matter Questions

List of magnetism and matter Questions

Question NoQuestionsClass
1Let the magnetic field on the earth be modelled by that of a point magnetic dipole at the centre of the earth. The angle of dip at a point the geographical
equator This question has multiple correct options
A. is always zero
B. can be zero at specific points
c. can be positive or negative
D. is bounded
12
2If a diamagetic solution is poured into a U-tube and one arm of this U-tube is
placed between the poles of a strong magnet, with the meniscus in line with the field, then the level of solution will :
A . rise
B. fall
c. oscillate slowly
D. remain as such
12
3The relative magnetic permeability of a magnetic material is 800 . Identify the nature of magnetic material and state its own properties.12
4Mention the desired properties of
magnetic materials used in making
electromagnets.
12
5A bar magnet is placed with its North pole pointing North. Neutral point is at a distance ‘d’ from the center of magnet.
The net magnetic induction at the same
distance on the axial line of the magnet.
A ( cdot 2 B_{H} )
в. ( 3 B_{H} )
( c . B_{H} )
D. ( 7 B ) н
12
6Magnetic field lines:
A. starts from north pole
B. starts from south pole
c. starts from current-carrying wires
D. are closed loops
12
7A bar magnet of magnetic moment ( 1.2 A m^{2} ) is placed in the magnetic
meridian with its south pole pointing the
north. If a neutral point is found at a
distance of ( 20 mathrm{cm} ) from the centre of the
magnet, the value of the horizontal
component of the earth’s magnetic field
is
( mathbf{A} cdot 3 times 10^{-5} T )
B ( .3 times 10^{-4} T )
( mathbf{c} cdot 3 times 10^{3} T )
D. ( 3 times 10^{-3} T )
12
8Dynamo is a device that converts.
A. Alternating current into direct current
B. Electrical energy into mechanical energy
C. Mechanical energy into electrical energy
D. Heat energy into electrical energy
12
9At two points separated by a distance of ( 3 mathrm{cm}, ) the magnetic field strength due to a short magnet on its axial line are in the ratio 512:125. Then the distance of magnet from the first point is:
A. ( 8 mathrm{cm} )
B. ( 11 mathrm{cm} )
( c cdot 4 c m )
D. 5cm
12
10The susceptibility of a paramagnetic substance was found for different
temperatures and a graph of ( chi ) against
( frac{1}{T} ) was plotted. From the graph, it was
found that what ( chi=0.5, frac{1}{T}=5 times )
( 10^{-3} / K . ) What is the curie constant for
the substance?
A. ( 50 k )
B. 75 K
c. ( 100 mathrm{k} )
D. 125 K
12
11The temperature, at which a
ferromagnetic material entirely loses its magnetic properties, is referred as
A. non magnetic point
B. curie point
c. van revolt point
D. none
12
12Which of the following figures
represents the magnetic lines of force
due to an isolated north pole?
( A )
B.
( c )
D.
12
13What do you mean by angle of inclination and horizontal component of magnetic field. Establish relation between them.12
14The use of Helmholtz coils is to produce
A. uniform magnetic field
B. non-uniform magnetic field
c. varying magnetic field
D. zero magnetic field
12
15( chi_{1} ) and ( chi_{2} ) are susceptibility of ( a )
paramagnetic material at
temperatures ( T_{1} K ) and ( T_{2} K )
respectively, then
A ( cdot x_{1}=x_{2} )
в. ( chi_{1} T_{1}=chi_{2} T_{2} )
c. ( chi_{1} T_{2}=chi_{2} T_{1} )
D cdot ( chi_{1} sqrt{T_{1}}=chi_{2} sqrt{T_{2}} )
12
16Mark correct option or options:
A. Electric field and magnetic field are basically independent
B. Electric field and magnetic field are two aspect of the electromagnetic field
C. Electric field and magnetic field may be produced by charge in rest
D. Both ( (a) ) and
( (c) ) are correct
12
17Depending on the magnetic property
the materials are classified in to
diamagnetic, paramagnetic and ferro magnetic. The behaviour of magnetic field lines near a magnetic substance is shown in the figure. Which material corresponds to the figure.
12
18The distance between two magnetic
poles is doubled and their pole-strength is also doubled. The force between them
A. Increases to four times
B. Decreases by half
c. Remains unchanged
D. Increases to two times
12
19Hysteresis loops for two magnetic
materials ( A ) and ( B ) are given below:
These materials are used to make
magnets for electric generators, transformer core and electromagnet
core. Then it is proper to use:
A. A for electric generators and transformers
B. A for electromagnets and B for electric generators
c. A for transformer and B for electric generators
D. B for electromagnets and transformers
12
20At the magnetic poles of magnet, its attractive power is minimum
A. True
B. False
12
21Write two properties of magnetic lines
of force.
12
22A loop of area ( 1 mathrm{m}^{2} ) is placed in a magnetic
field ( B=2 T, ) such that plane of the loop
is parallel to the magnetic field. If the loop is rotated by 180 , the amount of net charger passing through any point of loop, if its resistance is ( 10 Omega ) is then
A. ( 0.4 mathrm{c} )
B. ( 0.2 mathrm{c} )
c. ( 0.8 mathrm{c} )
D. o c
12
23Which of the following instruments is
used to measure magnetic field?
A. Thermometer
B. Pyrometer
c. Hygrometer
D. Flux meter
12
24Two parallel conductors are placed at
right angles to metre scale, at the 2 cm
and ( 6 mathrm{cm} ) marks, as shown. They carry
currents of ( 1 A ) and ( 3 A ) respectively as
shown in fig. They will produce zero magnetic field at the
A. Zero mark
B. ( 10 mathrm{cm} ) mark
c. ( 3 c m ) mark
D. ( 6 mathrm{cm} ) mark
12
25A student uses a magnetic compass to
perform a laboratory experiment in the Northern Hemisphere. She then carries the same magnetic compass with her to the Southern Hemisphere, taking care not to damage the compass in any way. When she reaches her destination at the equivalent latitude and longitude in the Southern Hemisphere, she prepares to perform the same laboratory experiment. The student looks at the compass before performing the experiment to see if the compass needle has changed. How has the compass changed?
A. The compass needle points ( 90^{circ} ) to the left of the expected direction
B. The compass needle points ( 90^{circ} ) to the right of the expected direction
c. The compass needle slowly rotates in a counter clockwise direction
D. The compass needle slowly rotates in a clockwis tion
as been no he co
12
26In the above figure, tube A contains
copper fillings and tube B contains aluminum fillings. If a strong magnet is
brought close to the two tubes as shown
in the figure, then
(A) Centre of gravity of the tube A move
towards the right
(B) Centre of gravity of tube B move
towards the right
A. Only A is true
B. Only B is true
c. Both ( A ) and ( B ) are true
D. Neither A nor B is true
12
27Force between two identical bar
magnets whose centres are ( r ) metre
apart is ( 4.8 N ), when their axes are in
the same line. If separation is increased
to ( 2 r, ) the force between them is
reduced to.

This question has multiple correct options
A . ( 0.3 N )
B. ( 0.6 N )
c. ( 2.4 N )
D. ( 1.2 N )

12
2828. A magnetic needle of magnetic moment 60 Am is directed
towards the geographical north at a place. It experiences
a torque of 1.2 x 10 Nm. If the earth’s horizontal
component of that place is 40 u Wb m then the angle
of decimation at that plane will be
(a) 30°
(b) 45°
(c) 60°
(d) 90°
12
29Find the magnetic field at P due to the
arrangement shown
A ( cdot frac{mu_{0} i}{sqrt{2} pi d}left(1-frac{1}{sqrt{2}}right) & )
B. ( frac{2 mu_{0} i}{sqrt{2} pi d} )
c. ( frac{mu_{0} i}{sqrt{2} pi d} )
D. ( frac{mu_{0} i}{sqrt{2} pi d}left(1+frac{1}{sqrt{2}}right) )
12
30(AUDOD 00)
(U) 10
8. A magnetic needle is kept in a non-uniform magnetic
field. It experiences
(a) a force but not torque
(b) a force and a torque
(c) neither a force, nor a torque
(d) a torque but not force
(AIEEE 2005)
12
31The upper limit temperature of a super conductor is
( mathbf{A} cdot 115 mathrm{K} )
B. 120 K
c. ( 125 mathrm{k} )
D. ( 130 mathrm{K} )
12
32The ratio of magnetic fields due to a bar
magnet at the two axial points ( P_{1} ) and
( P_{2} ) which are separated from each other
by ( 10 mathrm{cm} ) is ( 25: 2 . ) Point ( P_{1} ) is situated at
10cm from the centre of the
magnet.Points ( P_{1} ) and ( P_{2} ) are on the
same side of magnet and distance of ( boldsymbol{P}_{2} )
from the centre is greater than distance
of ( P_{1} ) from the centre of magnet,then magnetic length is
A. ( 5 mathrm{cm} )
B. ( 10 mathrm{cm} )
c. ( 15 mathrm{cm} )
D. ( 20 mathrm{cm} )
12
33If a magnet is suspended at angle ( 30^{circ} ) to the magnet meridian, the dip of
needle makes angle of ( 45^{circ} ) with the horizontal, the real dip is
( ^{A} cdot tan ^{-1}left(frac{sqrt{3}}{2}right) )
B ( cdot tan ^{-1}(sqrt{3}) )
( ^{mathrm{c}} tan ^{-1}(sqrt{frac{3}{2}}) )
D ( cdot tan ^{-1}left(frac{2}{sqrt{3}}right) )
12
34The horizontal component of the earth’s
magnetic field at a place is ( B ) and angle
of dip is ( 60^{circ} . ) What is the value of vertical component of earth’s magnetic field at equator?
12
35Choose the correct alternative, in
relation to properties of magnetic lines of force.
A. Magnetic lines of force start from south pole and end on north pole
B. Magnetic lines of force intersect each other at the poles
c. Magnetic lines of force are far from each other where the field is strong
D. Tangent at any point on the magnetic lines of force gives the direction of the magnetic field at that point.
12
36If a dip circle is placed in a vertical
plane at an angle of ( 30^{circ} ) to the magnetic meridian, the dip needle makes an angle of ( 45^{circ} ) with the horizontal. The real
dip at that place is?
A ( cdot tan ^{-1}(sqrt{3} / 2) )
B. ( tan ^{-1}(sqrt{3}) )
C ( cdot tan ^{-1}(sqrt{3} / sqrt{2}) )
D cdot ( tan ^{-1}(2 / sqrt{3}) )
12
37The earth is considered as a short
magnet with its centre coinciding with the geometric centre of earth. The angle of dip ( phi ) related to the magnetic latitude
( alpha lambda ) as
( ^{mathbf{A}} cdot tan phi=frac{1}{2 tan alpha} )
B. ( tan lambda=tan phi )
c. ( tan lambda=2 tan phi )
D. ( tan phi=2 tan lambda )
12
38The strength of the Earth’s magnetic field is?
A. Constant everywhere
B. Zero everywhere
c. Having very high value
D. Varying from place to place on the Earth’s surfact
12
39The vertical component of earth’s magnetic field at a place is ( sqrt{3} ) times the horizontal component the value of angle of dip at this place is
A ( .30^{circ} )
В ( cdot 45^{circ} )
( c cdot 60^{0} )
D. ( 90^{circ} )
12
40At a place, the horizontal and vertical components of earth’s magnetic field are equal. What is the angle of dip at that place?
A . 45
B. 55
( c cdot 65 )
D. 76
12
41Relative permittivity and permeability
of a material are ( epsilon_{mathrm{r}} ) and ( mu_{mathrm{r}}, ) respectively.
Which of the following values of these quantifies are allowed for a diamagnetic material?
A ( cdot epsilon_{mathrm{r}}=0.5, mu_{mathrm{r}}=0.5 )
B . ( epsilon_{mathrm{r}}=1.5, mu_{mathrm{r}}=1.5 )
( mathbf{c} cdot epsilon_{mathrm{r}}=0.5, mu_{mathrm{r}}=1.5 )
D. ( epsilon_{mathrm{r}}=1.5, mu_{mathrm{r}}=0.5 )
12
42Magnetic field can be defined as the:
A. space surrounding the magnet in which magnetic force acts
B. space surrounding the magnet in which electric force acts
C. space surrounding the magnet in which no force acts
D. none
12
43A current carrying loop is placed in a uniform magnetic field pointing in negative z direction. Branch PQRS is a tree quarter circle, while branch PS is straight. If force on branch PS is ( mathrm{F} ), force on branch PQR is:
( A cdot sqrt{2} F )
в. ( frac{F}{sqrt{2}} )
с. ( frac{pi F}{sqrt{2}} )
( mathbf{D} cdot sqrt{2} pi F )
12
44The magnetic susceptibilty for diamagnetic materials is
A. small and negative
B. small and positive
c. large and positive
D. large and negative
12
45The equatorial magnetic field of earth is
0.4G. Then its dipole moment on equator is
A ( cdot 1.05 times 10^{23} mathrm{Am}^{2} )
В. ( 2.05 times 10^{23} mathrm{Am}^{2} )
c. ( 1.05 times 10^{21} A m^{2} )
D. ( 2.05 times 10^{21} mathrm{Am}^{2} )
12
46Consider the Earth as a short magnet with its centre coinciding with the centre of the Earth and dipole moment
is ( M . ) The angle of dip ( delta ) is related to latitude ( lambda ) as :
( A cdot tan delta=tan lambda )
B. ( tan delta=2 tan lambda )
( c cdot tan delta=frac{tan lambda}{2} )
D. ( tan delta=cot lambda )
12
47The permanent magnetic moment of
the atoms of a material is not zero. The
material :
A. must be paramagnetic
B. must be diamagnetic
c. must be ferromagnetic
D. may be paramagnetic
12
48What is the phenomenon shown by ferromagnetic substances whereby the magnetic flux through the medium on magnetising field as well as previous
state of the substance?
A. Irradiation
B. Hysteresis
c. Inversion
D. Magnetostriction
12
49Out of given paramagnetic substance (Calcium, Chromium, Oxygen and Tungsten) which substance has maximum susceptibility?
A. Calcium
B. Chromium
c. oxygen
D. Tungsten
12
50A susceptibility of a certain magnetic material is ( 400 . ) What is the class of the
magnetic material?
A. Diamagnetic
B. Paramagnetic
c. Ferromagnetic
D. Ferroelectric
12
51Electromagnets are made of soft iron
because soft iron has
A. high susceptibility and low retentivity
B. low susceptibility and high retentivitty
c. low susceptibility and low retentivity
D. high susceptibility and high retentivity
12
52The variation of magnitude field ( (B) )
due to circular coil as the distance ( boldsymbol{X} )
varies is shown in the graph.
Which of the following is false?
A. Point ( A ) and ( A^{prime} ) are known as point of zero curvature.
B. ( B ) varies linearly with ( X ) at point ( A ) and ( A^{prime} )
( frac{d B}{d t}=0 ) at point ( A ) and ( A^{prime} )
( frac{d^{2} B}{d t^{2}}=0 ) at point ( A ) and ( A^{prime} )
12
53A long horizontal metallic rod with length along the east-west direction is falling under gravity. The potentiol difference between its two ends will :
A. be zero
B. be constant
c. increase with time
D. decrease with time
12
54At a place the angle of dip is ( 30^{circ} ). If the horizontal component of the earth’s magnetic field is ( H, ) then the total field
intensity will be given by
A ( cdot frac{H}{2} )
в. ( frac{2 H}{sqrt{3}} )
c. ( frac{H}{sqrt{2}} )
D. ( H sqrt{2} )
12
55The magnet is strongest near the
A. Poles of the magnet
B. Ends of the magnet
C. Centre of the magnet
D. One quarter point from the poles of the magnet
12
56Which of the following statement
related to hysteresis loop is incorrect?
A. The curve of B against H for a ferromagnetic material is called hysteresis loop
B. The area of B-H curve is a measure of power dissipated per cycle per unit area of the specimen
C. Coercitivity is a measure of the magnetic field required to destroy the residual magnetism of ferromagnetic material
D. The retentivity of a specimen is the measure of magnetic field remaining in the specimen when the magnetising field is removed
12
57A current of ( 10 A ) is flowing in a
equilateral triangle of side length ( ell= )
( 1 m ) as shown in figure. The magnetic
field at centre of triangle is :
A ( cdot 8 times 10^{-6} T )
В. ( 9 times 10^{-5} T )
c. ( 9 times 10^{-6} T )
D. ( 10^{-5} T )
12
58Assertion: The magnetic field lines of the earth resemble that of a magnetic
dipole located at the centre of the earth. Reason: The axis of the dipole coincide with the axis of rotation of the earth.
A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true and reason is not the correct explanation of assertion.
c. If assertion is true but reason is false
D. If both assertion and reason are false
12
59At a certain location in Africa, a
compass points ( 12^{circ} ) west of the
geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian
points ( 60^{circ} ) above the horizontal. The
horizontal component of the Earth’s
field is measured to be ( 0.16 G . ) Specify the direction and magnitude of the Earth’s field at the location.
A ( cdot 32^{circ} ) west of geographic meridian and ( 3.2 times 10^{-4} T )
B . ( 12^{circ} ) west of geographic meridian and ( 0.32 times 10^{-4} mathrm{T} )
C. ( 12^{circ} ) east of geographic meridian and ( 0.32 times 10^{-4} mathrm{T} )
D. ( 32^{circ} ) east of geographic meridian and ( 3.2 times 10^{-4} T )
12
60(a) Why does a paramagnetic sample display greater magnetisation (for the same magnetising field) when cooled?
(b) Why is diamagnetism, in contrast, almost independent of temperature?
(c) If a toroid uses bismuth for its core,
will the field in the core be (slightly) greater or (slightly) less than when the core is empty?
(d) Is the permeability of a ferromagnetic material independent
of the magnetic field? If not, is it more for lower or higher fields?
(e) Magnetic field lines are always nearly normal to the surface of a ferromagnet at every point. (This fact is analogous to the static electric field lines being normal to the surface of a conductor at every point.) Why?
(f) Would the maximum possible magnetisation of a paramagnetic sample be of the same order of magnitude as the magnetisation of a ferromagnet?
12
61toppr
Q Type your question.
uniform magnetic field ( B ) with constant velocity ( boldsymbol{v} ) at ( t=0 . ) The longest side of the frame is perpendicular to the direction of velocity If i is the instantaneous current through the frame then choose the alternative
showing the correct variation of i with time
( A )
( (mathrm{A}) )
в.
( (mathrm{B}) )
( c )
( (mathrm{C}) )
( D )
( (mathrm{D}) )
12
62According to Curie’s law, the magnetic susceptibility of a substance
at an absolute temperature T is proportional to –
A. ( 1 / T )
в. ( T )
c. ( 1 / T^{2} )
D. ( T^{2} )
12
63Magnetic lines of force always cross
each other. Is the given statement true or false? Justify.
12
64.P
A uniform but time-varying magnetic field B(1) exists in
a circular region of radius a and is directed into the plane
of the paper, as shown. The magnitude of the induced
electric field at point P at a
distance r from the centre of x x Bt) x 2 .
the circular region
(a) is zero
x x x x x
(b) decreases as 1/r
(c) increases as r
(d) decreases as 1/r?
12
65A ship is travelling due east according to
mariner’s compass. If the declination at
that place is ( 20^{circ} ) east, the actual direction
of its motion is
A ( cdot 40^{circ} ) south of east
B. ( 20^{circ} ) south of east
C ( cdot 5^{circ} ) south of east
D. ( 20^{circ} ) north of east
12
66At a certain place, the angle of dip ( 30^{circ} ) and the horizontal component of earth’s
magnetic field is 0.50 oerested.The earth’s total magnetic field (in oerested) is
A. ( sqrt{3} )
B.
c. ( frac{1}{sqrt{3}} )
D. ( frac{1}{2} )
12
67Two equal poles repel each other with a
force of ( 10^{-3} ) N. When placed 2 cm apart in
air, the pole strength of each is (in amp-
( mathrm{m}) )
A . ( 4 pi )
B. 2
( c cdot 4 )
D. 2pi
12
68Assertion
The net magnetic force on a current loop in a uniform magnetic field is zero but torque may or may not be zero
Reason
Torque on a current carrying coil in a magnetic field is given by ( bar{tau}= ) ( boldsymbol{n} boldsymbol{I}(overline{boldsymbol{A}} boldsymbol{X} overline{boldsymbol{B}}) )
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
69The angle of dip at the location in
southern India is about ( 18^{circ} . ) Would you
expect a greater or a smaller dip angle in Britain (Closer to the north pole.)
12
70Of dia, para and ferromagnetism, the universal property of all substance is
A. diamagnetism
B. paramagnetism
c. ferromagnetism
D. all of the above
12
71A small magnet is suspended freely by a vertical string. The horizontal and vertical components of Earth’s field is ( 20 mu T ) and ( 30 mu T ) respectively. Find the
angle from horizontal at which magnet will stay in equilibrium.
A ( cdot tan ^{-1}left(frac{3}{2}right) )
B ( cdot tan ^{-1}left(frac{2}{3}right) )
( ^{c} cdot sin ^{-1}left(frac{2}{3}right) )
D. ( cos ^{-1}left(frac{2}{3}right) )
12
72The dimensions of the ratio of magnetic
flux ( (phi) ) and permeability ( (mu) ) are?
( mathbf{A} cdotleft[M^{0} L^{1} T^{0} A^{1}right] )
B. ( left[M^{0} L^{-3} T^{0} A^{1}right] )
c. ( left[M^{0} L^{1} T^{1} A^{-1}right] )
D・ ( left[M^{0} L^{2} T^{0} A^{1}right] )
12
73The B-H curve (i) and (ii) shown in fig.,
associated with
A. (i) diamagnetic and (ii) paramagnetic substance
B. (i) paramagnetic and (ii) ferromagnetic substance
C. (i) soft iron and (ii) steel respectively
D. (i) steel and
(ii) soft iron respectively
12
74Magnetic lines of force
A. are mere directions
B. have no physical reality
C. can be used to indicate the direction of the magnetic field at point
D. all the above are correct
12
75A body at rest starts from a point at a distance ( r(>R) ) from the center of the
earth. If ( mathrm{M} ) and ( mathrm{R} ) stand for the mass and
the radius of earth respectively, then the speed of the body when it reaches the Earth surface is
( ^{mathrm{A}} cdot sqrt{frac{2 G M}{R}} )
в. ( sqrt{frac{2 G M}{R-r}} )
c. ( sqrt{frac{2 G M(r-R)}{R r}} )
D. zero
12
76Explain ferromagnetism on the basis of domain theory?12
77Two isolated point poles of strength ( 30 A m ) and ( 60 A m ) are placed at a
distance of ( 0.3 m . ) The force of repulsion
is:
A ( cdot 2 times 10^{-3} N )
B . ( 2 times 10^{-4} N )
c. ( 2 times 10^{5} N )
D. ( 2 times 10^{-5} N )
12
78The distance between two magnetic poles is doubled and their pole-strength is also doubled. The force between them
A. Increases to three times
B. Decreases by half
c. Remains unchanged
D. Increases to two times
12
79Relative permittivity and permeability of
a material are ( varepsilon_{r} ) and ( mu_{r} ) respectively. The
values of these quantities allowed for a diamagnetic material are
( mathbf{A} cdot varepsilon_{r}=0.5, mu_{r}=1.5 )
( mathbf{B} cdot varepsilon_{r}=1.5, mu_{r}=0.5 )
( mathbf{c} cdot varepsilon_{r}=0.5, mu_{r}=0.5 )
( mathbf{D} cdot varepsilon_{r}=1.5, mu_{r}=1.5 )
12
80Derive an expression for the intensity of magnetic field on broad side on position due to a bar magnet.12
81Conductivity of metal decreases with
temperature while conductivity of electrolytic conductors increases with temperature. Why?
12
82allel
39. A current carrying coil is placed with its axis perpendicula
to N-S direction. Let horizontal component of earth
magnetic field be H, and magnetic field inside the lo
is H. If a magnet is suspended inside the loop, it makes
angle with H. Then 0 =
( H )
(a) tan
Its
bout
I be
(b) tan-1
H
CA
(c)
cosec-1
ace
ce,
(d) cott H,
Но )
12
83The given figure represents a material
which is
A. Paramagnetic
B. Diamagnetic
c. Ferromagnetic
D. Ferrimagnetic
12
84The plane of a dip circle is set in the geographic meridian. Then the apparent
dip is ( left(delta_{1} text { is the actual dip and } delta_{2} ) is the right. declination):
A ( cdot theta=tan ^{-1}left(frac{tan delta_{1}}{tan delta_{2}}right) )
B . ( theta=tan ^{-1}left(tan delta_{1} cos delta_{2}right) )
c. ( theta=tan ^{-1}left(frac{tan delta_{2}}{cos delta_{1}}right) )
D. ( theta=tan ^{-1}left[tan delta_{1} cos delta_{2}right] )
12
85What is the direction of magnetic field at the centre of a coil carrying clockwise current?
A. No direction
B. normal to the axis of coil inwards
c. Along the axis of coil inwards.
D. Along the axis of coil outwards
12
86The purpose of soft iron cylinder
between the pole pieces of the horse-
shoe magnet in a moving
coil galvanometer is
A. to increase the magnetic induction in the polar
( operatorname{gap} )
B. to evenly distribute the magnetic lines of force
C. to provide a radial magnetic field
D. to reduce the magnetic flux leakage in the polar
( operatorname{gap} )
12
87Two short bar magnets with magnetic
moments 400 ab-amp ( c m^{2} ) and 800 ab
amp ( c m^{2} ) are placed with their axis in
the same straight line with similar poles facing each other and with their
centres at ( 20 mathrm{cm} ) from each other. Find
the force of repulsion.
12
88The figure shows the various positions (labelled by subscripts) of small
magnetised needles ( P ) and ( Q ). The arrows
show the direction of their magnetic
movement.configuration corresponds to
the lowest potential energy among all
the configurations shown
A . ( P Q_{3} )
в. ( P Q_{4} )
( c cdot P Q_{5} )
D. ( P Q_{6} )
12
89Angle of dip is ( 90^{circ} ) at:
A. Equator
B. Middle point
c. Poles
D. None of these
12
90A paramagnetic substance when placed in an externally applied non-uniform magnetic field tends
to
A. increase the applied field
B. decrease the applied field
c. vary the applied field
D. change the applied field
12
91If a diamagnetic substance is brought
near the north or the south pole of a bar magnet, it is
A. attracted by both the poles
B. repelled by both the poles
c. repelled by the north pole and attracted by the south pole
D. attracted by the north pole and repelled by the south pole
12
92Show diagramatically the behavior of magnetic field lines in the presence of
(i) paramagnetic and
(ii) diamagnetic substances. How does one explain this distinguishing feature.
12
93The horizontal component of earth’s magnetic field at a place is ( frac{1}{sqrt{3}} ) times
the vertical component. Determine the angle of dip at that place.
12
94Two magnets of equal mass are joined at right angles to each other as shown Magnet 1 has a magnetic moment 3
times that of magnet 2. This arrangement is pivoted so that it is free to rotate in the horizontal plane. In
equilibrium what angle will the magnet
1 subtend with the magnetic meridian
A ( cdot tan ^{-1}left(frac{1}{2}right) )
B. ( tan ^{-1}left(frac{1}{3}right) )
( c cdot tan ^{-1}(1) )
D. ( 0^{circ} )
12
95Critical temperature can be defined as
the
A. Temperature at which there is no motion between the molecules
B. Temperature at which a gas is converted into its liquid state
C. Temperature at which volume of a gas becomes zero
D. Temperature above which a gas cannot be liquefied no matter however high the pressure may be
12
9648. The variation of magnetic susceptibility (X) with absolute
temperature T for a ferromagnetic material is
X4
XA
(b)
-TOLT
S
of
T
آاها
49 Thor 1/Troph for an alloy of
12
97The armature of de motor has ( 20 Omega )
resistance .It draws current of 1.5
ampere when run by 220 volts dc supply. The value of back e.m.f. induced in it will be
( A cdot 190 V )
B. 150 V
c. ( 170 v )
D. ( 120 mathrm{V} )
12
98The strength of a magnet is in
the middle and
A. weakest, weakest
B. strongest, strongest
c. weakest, strongest
D. strongest, weakest
12
99The force required just to move a body up an inclined plane is double the force required just to prevent the body sliding down. If the coefficient of a fraction is
( 0.25, ) the angle of inclination of the plane is
A ( cdot 36.8 )
B . 45
( c .30 )
D. ( 42.6^{circ} )
12
100Identify the contour lines along which the dip measured at the Earth’s surface
is equal in magnitude.
A. Aclinic lines
B. Isoclinic lines
c. Isogonic lines
D. Agonic lines
12
10170. A bar magnet has coercivity 4 10′ Am. It is desired
to demagnetise it by inserting it inside a solenoid 12 cm
long and having 60 turns. The current that should be sent
through the solenoid is
(a) 2 A
(b) 4A
(c) 6 A
(d) 8A
12
102Two identical magnetic dipoles are
placed, as shown separated by distance
d. The magnetic field, mid way between
the dipoles, is :
( A )
[
frac{mu_{0} M sqrt{2}}{4 pi d^{3}}
]
B.
[
frac{mu_{0} M sqrt{5}}{4 pi d^{3}}
]
( c )
[
frac{2 mu_{0} M sqrt{5}}{pi d^{3}}
]
D. none of these
12
103Write two examples of ferromagnetic
substance.
12
104Which of the following statements is wrong? Magnetic lines of force
A. Form closed circuits
B. Never intersect
c. Are densest near the poles
D. None of the above
12
105The magnetic field of the earth can be modelled by that of a point dipole placed at the centre of the earth. The
dipole axis makes an angle of ( 11.3^{circ} )
with the axis of the earth. At Mumbai,
declination is nearly zero. Then
A. the declination varies between ( 11.3^{circ} mathrm{W} ) to ( 11.3^{circ} mathrm{E} )
B. the least declination is ( 0^{circ} )
C. the plane defined by dipole axis and Earth axis passes through Greenwich
D. declination averaged over Earth must be always negative
12
10616. The resistance in the following circuit is increased at a
particular instant. At this instant the value of resistance is
10 12. The current in the circuit will be now
10 mH
W
5v
(a) i = 0.5 A
(c) i 0.5 A
(d) i = 0
12
107An aeroplane is flying from city ( A ) to ( B ) along path 1. The path 1 is a circular arc whose centre coincides with the centre
of the earth. Another aeroplane is flying along path 2 from ( A ) to ( B ). The path 2 is
circular arc whose centre is at ( mathrm{C} ). O is
the centre of the earth. Then
A. The distance travelled by ( 1^{s t} ) aeroplane is greater than that of ( 2^{n d} ) aeroplane
B. The distance travelled by ( 1^{text {st}} ) aeroplane is less than that of ( 2^{n d} ) aeroplane
c. The displacement of both aeroplane is different
D. None of these
12
108How will you quantize the relative permeability of a paramagnetic
substance ?
A. Much more than one
B. Slightly more than one
c. Less than one but greater than zero
D. zero
12
109At a certain location in Africa, a
compass points ( 12^{circ} ) west of the
geographic north. The north tip of the magnetic needle of a dip circle placed in the plane of magnetic meridian
points ( 60^{circ} ) above the horizontal. The
horizontal component of the earth’s field is measured to be 0.16 G. Specify the direction and magnitude of the earth’s field at the location.
12
110State whether true or false.
A magnetic field is a region around a magnet where magnetic lines of force
act
A. True
B. False
12
111Assertion
The magnetic poles of earth do not coincide with the geographic poles.
Reason
The discrepancy between the orientation of a compass and true north-south direction is known as
magnetic declination.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
112Rajkumar said to you that the magnetic field lines are open and they start at north pole of bar magnet and end at south pole. What questions do you ask Rajkumar to correct him by sayingfield lines are closed?12
113A ferromagnetic material is heated above its curie temperature. Which one of a correct statement?
A. Ferromagneitc domains are perfectly arranged
B. Ferromagnetic domains become random
c. Ferromagnetic domains are not influenced
D. Ferromagnetic material changes into diamagnetic material
12
114A telephone cable at a place has four long straight horizontal wires carrying a current of ( 1.0 mathrm{A} ) in the same direction
east to west. The earth’s magnetic field at the place is ( 0.39 mathrm{G}, ) and the angle of
dip is ( 35^{circ} . ) The magnetic declination is
nearly zero. What are the resultant magnetic fields at points 4.0 ( mathrm{cm} ) below the cable?
12
115Explain the term hysteresis.12
116Three identical bars ( A, B ) and ( C ) are
made of different magnetic materials. When kept in a uniform magnetic field, the field lines around them look as
given in the figure. Make the
correspondence of these bars with their material being diamagnetic (D), ferromagnetic (F) and paramagnetic (P)
A. ( A leftrightarrow F, B leftrightarrow D, C leftrightarrow P )
в. ( A leftrightarrow D, B leftrightarrow P, C leftrightarrow F )
c. ( A leftrightarrow F, B leftrightarrow P, C leftrightarrow D )
D. ( A leftrightarrow P, B leftrightarrow F, C leftrightarrow D )
12
117Which metal is suitable to use to make
a permanent magnet?
A. Aluminium
B. Brass
c. Iron
D. stee
12
118If the liquid in a U-tube rises to high level in the limb placed between poles of an electromagnet, then the liquid is:
A. non-magnetic
B. diamagnetic
c. paramagnetic
D. ferromagnetic
12
119Q Type your question
temperature (T) is represented then by
( A )
( B )
( c )
( D )
12
12062. A coil in the shape of an equilateral triangle of side
0.02 m is suspended from its vertex such that it is hanging
in a vertical plane between the pole pieces of permanent
magnet producing a uniform field of 5 x 10-2T. If a current of
0.1 A is passed through the coil, what is the couple acting?
(a) 5/3×10-7 N-m (b) 513×10-10 N-m
(c) 2×10-7 N-m
(d) None of these
12
121Iron is ferromagnetic:
A. at all temperatures
B. at NTP only
C . above ( 770^{circ} mathrm{C} )
D. below ( 770^{circ} mathrm{C} )
12
12214. Two short bar magnets of length 1 cm each have
magnetic moments 1.20 Am and 1.00 Am², respectively.
They are placed on a horizontal table parallel to each
other with their N poles pointing towards the south. They
have a common magnetic equator and are separated by a
distance of 20.0 cm. The value of the resultant horizontal
magnetic induction at the mid-point 0 of the line joining
their centres is close to (horizontal component of earth’s
magnetic induction is 3.6 x 10- Wb/m?)
(a) 2.56 x 104 Wb/m2 (b) 3.50 x 10+Wb/m²
(c) 5.80 x 104 Wb/m² (d) 3.60 x 10-Wb/m²
(JEE Main 2013)
12
123The vertical plane which passes through the magnetic axis of a freely suspended magnetic at rest is called
A. Magnetic meridian
B. Geographical meridian
c. North meridian
D. South meridian
12
124Assertion
Basic difference between an electric
line and magnetic line of force is that former is discontinuous and the later is
continuous or endless.
Reason
No electric lines of force exist inside a
charged body but magnetic lines do
exist inside a magnet.
A. Both Assertion and Reason are correct and Reason is the correct explanation of Assertion
B. Both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion
C. Assertion is correct but Reason is incorrect.
D. Assertion is incorrect but Reason is correct.
12
125(a) An iron ring of relative permeability
( mu_{r} ) has windings of insulated copper
wire of ( n ) turns per metre. When the
current in the windings is ( I ), find the expression for the magnetic field in the
ring.
(b) The susceptibility of a magnetic material is ( 0.9853 . ) Identify the type of magnetic material. Draw the modification of the field pattern on
keeping a piece of this material in a uniform magnetic field.
12
126Curie-Weiss law is obeyed by iron.
A. At curie temperature only
B. At all temperatures
C . Below curie temperature
D. Above curie temperature
12
127Which of the following materials which lack permanent magnetic dipoles?
A. diamagnetic
B. ferromagnetic
c. semimagnetic
D. none of the above
12
128The hysteresis cycle for the material of permanent magnet is
A. Short and wide
B. Tall and narrow
c. Tall and wide
D. short and narrow
12
129In the hysteresis cycle, the value of ( boldsymbol{H} ) needed to make the intensity of magnetism zero is called
A. Retentivity
B. Coercive force
c. Lorentz force
D. None of the above
12
130Define Curie temperature in
magnetism.
12
131Bell laboratory has developed superconductor at a temperature of
A. 30 K
в. 40 к
( c . ) 50 ( k )
D. 60
12
132Draw a labelled diagram of a moving coil galvanometer and explain its
working. What is the function of radial magnetic field inside the coil?
12
133At a certain place, horizontal component is ( sqrt{3} ) times the vertical component. The angle of dip at this place is:
A .
в. ( pi / 3 )
c. ( pi / 6 )
D. none of these
12
134The coercivity of a magnet is ( 3 x )
( 10^{3} A m^{-1} . ) What current should be
passed through a solenoid of length ( 10 mathrm{cm} ) and number of turns 50 that the
magnet is demagnetized when inserted in it?
A ( .3 A )
в. ( 6 A )
c. ( 9 A )
D. ( 12 A )
12
135A clinic lines on magnetic map
represent the lines of
A. zero declination
B. equal declination
c. zero dip
D. equal dip
12
136The value of angle of dip at magnetic poles of the Earth is12
137The current in the coil is reversed, and
the coil is rotated about its vertical axis
by an angle of ( 90^{circ} ) in the anticlockwise
sense looking from above. Predict the direction of the needle. Take
the magnetic declination at the places to be zero.
12
138In a permanent magnet at room
temperature
A. magnetic moment of each molecule is zero
B. the individual molecules have non-zero magnetic moment which are all perfectly aligned
C . domains are partially aligned
D. domains are all perfectly aligned
12
139The force of repulsion between two similar magnetic poles each of strength
( 2 A m ) at a distance ( 2 m ) from each other
in vacuum is :
A ( cdot 10^{-5} N )
В. ( 10^{-7} N )
c. ( 10^{-3} N )
D. ( 2 times 10^{-7} N )
12
140A long straight wire of radius ( a ) carries a
steady current i. The current is uniformly distributed across its cross section. The ratio of the magnetic field ( operatorname{ata} / 2 ) and ( 2 a ) is:
A . ( 1 / 2 )
в. ( 1 / 4 )
( c cdot 4 )
D.
12
141Which of the following is minimum at the poles?
A. Angle of dip
B. Horizontal component of the earth’s magnetic field
c. Angle of declination
D. Vertical component of the earth’s magnetic field
12
142Two magnetic monopoles are kept apart by a distance ‘d’. The magnetic force acting on each pole is ‘F’. How much percentage must the distance between
the magnetic poles be changed so that the magnetic force acting on each pole be ( 4 mathrm{F} )
A . -10%
B . -20%
c. -40%
D . -50%
12
143The angle of inclination of the axis of
the magnetic needle to the horizontal plane when suspended freely and is at rest is known as
A. Angle of inclination
B. Angle of variation
c. Angle of declination
D. None of the above
12
144( P ) is the centre of the square ( B_{p}=? ) Four
( boldsymbol{L} ) shaped wires, each carrying current ( boldsymbol{I} )
Find the magnetic field at point ( boldsymbol{P} ) ?
A ( cdot 1 w b / m^{2} )
В. ( 0 w b / m^{2} )
( c cdot 2 w b / m^{2} )
D. none of these
12
145Point out the wrong statement about the magnetic properties of soft iron and
steel
A. Retentivity of soft iron is more than retentivity of steel
B. Coercivity of soft iron is less than coercivity of steel.
c. Area of B-H loop in soft iron is smaller than the area of B-H loop for steel
D. Area of B-H loop in soft iron is greater than the area of B-H loop for steel
12
146The temperature of transition from ferromagnetic property to paramagnetic property is called as:
A. Transition temperature
B. Critical temperature
c. Curie temperature
D. Triplet temperature
12
147Magnetic field of earth is identical to
magnetic field of a giant magnet held
( 20^{circ} ) west of geographic ( N-S ) at the
centre of earth. At equator, horizontal
component of earth is ( 0.32 G ). Vertical
component can be calculated from the
relation ( V=H ) tan ( delta, ) where ( delta ) is angle
of dip at the place. The value of ( boldsymbol{delta}=mathbf{0}^{boldsymbol{o}} ) at
equator and ( delta=90^{circ} ) at poles. What is
the order of magnetic declination at a place on earth :
A ( cdot 20^{circ} ) East
B . ( 10^{circ} ) East
c. ( 20^{circ} ) west
D. ( 10^{circ} ) west
12
148Write any three properties of magnetic
lines of force.
12
149A circular conductor of radius ( 5 mathrm{cm} )
produce magnetic field of ( 7 times 10^{-6} mathrm{T} )
The current flows through the conductor is
A. 3.0 A
B. 2.25 A
c. 4.5 A
D. 0.56 A
12
150Consider the earth as a short magnet
with the centre coinciding with the centre of the earth and dipole moment ( M ). The angle of dip ( theta ) at the place where the magnetic latitude is ( lambda ) is :
A ( cdot tan ^{-1}(2 tan lambda) )
B. ( tan ^{-1}(tan lambda) )
( c cdot tan ^{-1}(tan lambda / 2) )
D. ( tan ^{-1}(4 tan lambda) )
12
151Strength of earth’s magnetic field is of
the order of :
( mathbf{A} cdot 10^{-4} T )
B. ( 10^{-3} T )
c. ( 10^{-5} T )
D. ( 10^{-6} T )
12
152A short bar magnet is placed with its south pole pointing geographic North at a
place where ( B_{H}=0.4 ) gauss. The length
of the magnet is ( 10 mathrm{cm} ) and pole strength
is ( 16 A-m ). The distance of each null
point from the centre will be
A. ( 0.2 m ) on axial line
B. ( 0.8 mathrm{cm} ) on axial line
c. ( 0.4 mathrm{cm} ) on axial line
D. ( 0.2 mathrm{cm} ) on equitorial line
12
153The total intensity of the earth’s magnetic field at equator is 5 units. What is its value at the poles?
A . 5
B. 4
( c .3 )
D. 2
12
15450. Which of the following is true?
(a) Diamagnetism is temperature dependent
(b) Paramagnetic is temperature dependent
(c) Paramagnetic is temperature independent
(d) None of these
12
155The angles of dip at the poles and the equator respectively are :
A ( cdot 30^{0}, 60^{circ} )
( ^{0}, 66^{0} )
В. ( 90^{0}, 0^{0} )
c. ( 30^{0}, 90^{circ} )
D. ( 0^{0}, 0^{0} )
12
156Two magnetic monopoles are kept apart by a distance ‘d. The magnetic force acting on each pole is ‘ ( boldsymbol{F} ) “. How much percentage must the distance between the magnetic poles be changed so that the magnetic force acting on each pole
be ( 4 F )
A. Decreases by ( 50 % )
B. Decreases by 20%
c. Increased by ( 50 % )
D. Increased by ( 20 % )
12
157Properties of magnetic lines of force
are:
A. The imaginary lines which represent the direction of magnetic field, are known as magnetic lines of force.
B. Magnetic lines of force are closed curves.
C. Outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole.
D. All
12
158A galvanometer of number of turns 175
having ( 1 mathrm{cm}^{2} ) area, turns through ( 1^{circ} )
when a current of ( 1 m A ) is passed. Find
magnetic field if torsional constant of spring is ( 10^{-6} N-m )
A ( cdot 10^{-4} T )
B. ( 10^{-3} T )
c. ( 10^{-5} T )
D. ( 10^{-2} T )
12
159Q Type your question
ferromagnetic material can be ploted
as :
( A )
B.
( c )
( D )
12
160The magnetic field of the earth can be modelled by that of a point dipole placed at the centre of the earth. The
dipole axis makes an angle of ( 11.3^{circ} ) with the axis of the earth. At mumbai
declination is nearly zero. Then
A. the declination varies between ( 11.3^{circ} ) W to ( 11.3^{circ} ) E
B. the least declination is ( 0^{circ} )
c. the plane defined by dipole and the earth axis posses through greenwich
D. declination average over the earth must be always negative
12
161Alnico is used for making permanent
magnets because it has
A. High coercivity and high retentivity
B. high coercivity and low retentivity
C. low coercivity and low retentivity
D. low coercivity and high retentivity
12
162If I is the intensity of earth’s magnetic
field, H its horizontal component and ( V )
the vertical component, then these are
related as:
( mathbf{A} cdot I=V+H )
( mathbf{B} cdot I=sqrt{H^{2}+V^{2}} )
( mathbf{C} cdot I=sqrt{H^{2}-V^{2}} )
D ( cdot I=H^{2}-V^{2} )
12
163A bar magnet of length of ( 0.1 m ) has a
pole strength of 50 Am. Calculate the
magnetic field at a distance of ( 0.2 m ) from its centre on (i) its axial line and
(ii) its equatorial line.
12
164Which of the following is minimum at the equator?
A. Angle of dip
B. Horizontal component of earth’s magnetic field
c. Angle of declination
D. Intensity of the earth’s field
12
165A line joining places of equal declination
is called
A . aclinical
B. isoclinical
c. isodynamical
D. isogonal
12
166Write the causes of energy loss and ways to reduce them in transformer
(any four)
12
16721. The values of the apparent angles of dip in two planes at
right angles to each other are 300 and 45º. Then the true
value of the angle of dip at the place is
(a) tan-‘1
(b) tan-12
(c) cot-‘2
(d) cot-4
12
168A long magnet is cut into two equal parts such that the length of each half
is same as that of original magnet. If the period of original magnet is ( T, ) then
the period of new magnet is :
A. ( T )
в. ( T / 2 )
c. ( T / 4 )
D. ( 2 T )
12
169Ferrimagnetic those expected to have large magnetism but actually have small net magnetic moment e.g. magnetic ( left(boldsymbol{F} boldsymbol{e}_{3} boldsymbol{O}_{4}right), ) ferrites ( left(boldsymbol{M}^{2}+right. )
( F e_{2} O_{4} ) ). This is because of unequal
number of domains in opposite direction.
12
170Assertion
The ferromagnetic substance do not obey Curie’s law.
Reason
At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
171The variation of magnetic susceptibility with the temperature of a ferromagnetic material can be plotted
as?
( A )
в.
( c )
D.
12
172The susceptibility of magnetic material
is ( -4.2 times 10^{-6} . ) Name the type of
magnetic material it represents.
12
173Two magnetic poles one of which is three
times as strong as the other exert on each other, a force equal to ( 3 times 10^{-3} ) when
separated by a distance of ( 10 mathrm{cm} ). The
strength of the each pole is
( mathbf{A} .5 mathrm{Am}, 15 mathrm{Am} )
В. 30 Ат, 10 Ат
( mathbf{c} .20 mathrm{Am}, 60 mathrm{Am} )
D. ( 50 A m, 150 A m )
12
174in the magnetic meridian of a place, the horizontal component of the earth’s magnetic field is 0.26 and the dip angle
is 60 and the dip angle is 60 What is the magnetic field of the earth at this location?
12
175In a region of uniform magnetic
induction ( B=10^{-2} ) tesla, a circular coil
of radius ( 30 mathrm{cm} ) and resistance ( pi^{2} ) ohm is rotated about an axis, which is perpendicular to the direction of B and which forms a diameter of coil. If the
coil rotates at 200 r.p.m., the amplitude of alternating current induced in the coil is :-
A ( cdot 4 pi^{2} mathrm{m} )
B. 30 mA
( c cdot 6 m )
D. 200 mA
12
176Value of ( boldsymbol{H} ) on earth’s surface is
A. ( 0.32 G )
в. ( 0.32 T )
c. ( 0.32 times 10^{-4} G )
D. ( 0.32 times 10^{-5} T )
12
177If ( delta_{1} ) and ( delta_{2} ) are the angles of dip observed in two vertical planes at right angles to each other and ( delta ) is the true
value of dip then :
A ( cdot tan ^{2} delta=tan ^{2} delta_{1}+tan ^{2} delta_{2} )
B . ( cot ^{2} delta=cot ^{2} delta_{1}+cot ^{2} delta_{2} )
( ^{mathrm{C}} tan ^{2} delta=frac{tan ^{2} delta_{1}+tan ^{2} delta_{2}}{tan ^{2} delta_{1} tan ^{2} delta_{2}} )
D. ( cot ^{2} delta=1+cot ^{2} delta_{1} cos ^{2} delta_{2} )
12
178used to plot the magnetic field around a
bar magnetic field around a bar magnet
with poles marked ( N ) (North) and ( S ) (South). Which of the following diagrams correctly shows the expected
field pattern?
( A )
B.
( c )
( theta )
D.
12
179State whether the following statement
is True or False.

Ampere’s swimming rule describes the direction of magnetic lines of force in a straight conductor.

12
180Resultant force acting on a diamagnetic material in a magnetic field is in direction.
A. From stronger to the weaker part of the magnetic field
B. From weaker to the stronger part of the magnetic field
c. Perpendicular to the magnetic field
D. In the direction making ( 60^{circ} ) to the magnetic field
12
181The meniscus of a liquid contained in one of the limbs of a narrow U-tube is
held electromagnet with the meniscus in line with the field. The liquid is seen to rise. This indicates that the liquid is
A. anti-ferromagneticç
B. paramagnetic
c. diamagnetic
D. non-magnetic
12
182A dip circle is at right angle to the magnetic meridian. The apparent dip angle is
A. ( 0^{circ} )
B. ( 30^{circ} )
( c cdot 60^{circ} )
D. ( 90^{circ} )
12
183Three magnets of the same length but
moments ( mathrm{M}, 2 mathrm{M} ) and ( 3 mathrm{M} ) are arranged in the forms of an equilateral triangle with opposite pole nearer, the resultant
magnetic moment of the arrangement is?
A. 6 м
B. zero
c. ( sqrt{3} ) м
D. ( frac{sqrt{3}}{2} ) M
12
184Explain Curie’s law for a paramagnetic
substance.
12
185Hysteresis is shown by which of the following materials
A. paramagnetic only
B. ferromagnetic only
c. diamagnetic only
D. both B and C
12
186A charged particle, initially at rest at 0 when released follows a trajectory as
shown. Such a trajectory is possible in
the presence of.
A. Electric field of constant magnitude and varying direction
B. Magnetic field of constant magnitude and varying direction
C. Electric filed of constant magnitude and constant direction
D. Electric and magnetic fields of constant magnitudes and constant directions which are parallel to each other
12
187State Tangent Law in magnetism.12
188The force acting on a pole of strength of ( 20 mathrm{Am} ) is ( 8 times 10^{-4} mathrm{N}, ) when placed in a
magnetic field. The magnetic induction field strength is :
A. ( 4 times 10^{-6} ) т
B. ( 0.4 times 10^{4} mathrm{T} )
( c cdot 4 G )
D. ( 4 times 10^{-5} mathrm{T} )
12
18952. A paramagnetic material is kept in a magnetic field. The
field is increased till the magnetisation becomes constant.
If the temperature is now decreased, the magnetisation
(a) will increase (b) decreases
(c) remain constant (d) may increase or decrease
2
Ti
• 1-
1
12
190Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature,
then it will show:
A. paramagnetism
B. anti-ferromagnetism
c. no magnetic property
D. diamagnetism
12
191If a magnetic material is having magnetic susceptibility ( (chi)=-1, ) then
the relative magnetic permeability ( left(mu_{r}right) ) and type of magnetic material is?
A. ( 0, ) diamagnetic
B. 2, ferromagnetic
c. 1 , paramagnetic
D. -1, diamagnetic
12
192carrying current ( i_{0} ) lies in the ( x ) -y plane as shown in the figure. It is hinged at ( y^{-} )
axis so that it can freely route about it. Moment of inertia of the loop about an
axis through its c.m. and normal to its
plane is equal to ( gamma M a^{2} . A t t=0, ) an
external magnetic field of induction B is applied along +ve x axis. The initial angular acceleration of the loop is equal
to
A ( cdot frac{4 i_{0} B}{M(2 gamma+1)} )
В. ( frac{i_{0} B}{M gamma} )
c. ( frac{4 i_{0} pi B}{M(2 gamma+1)} )
D. ( frac{4 i_{0} B}{(2 gamma+1)} )
12
193Meena draws magnetic field lines of the
field close to the axis of a current
carrying circular loop. As she moves away from the center of the circular loop she observes that the lines keep
A. on diverging
B. on converging
c. diappearing
D. none
12
194The vertical component of earth’s magnetic field at a place is ( sqrt{3} ) times the horizontal component the value of angle of dip at this place is?
A ( .30^{circ} )
B . ( 45^{circ} )
( c cdot 60^{circ} )
D. ( 90^{circ} )
12
195Write two properties of a material suitable for making (a) a permanent magnet, and
(b) an electromagnet.
12
196Magnetic dipole moment is a vector quantity directed from:
A. south to North pole
B. North to south pole
c. East to west direction
D. west to East direction
12
197A frog can jump higher than normal in a magnetic field because the tissues of a
frog are
A. paramagnetic
B. diamagnetic
c. ferromagnetic
D. antiferro magneticc
12
198Two magnetic dipoles are lying as
shown in figure. the separation ‘ ( d )
between them is very large. A point
charge ( Q ) is projected with some speed ( v ) as shown. The force experienced by
the charged particle is:
A . 0
B. ( frac{4 sqrt{2} mu_{0} M Q v}{pi d^{3}} )
c. ( frac{sqrt{2} mu_{0} M Q v}{pi d^{3}} )
D. ( frac{2 sqrt{2} mu_{0} M Q v}{pi d^{3}} )
12
199Which of the following is/are true for “magnetic lines of force around a bar magnet”?
A. are closed continuous curves
B. travel from north to south outside the magnet
c. bend around the length of magnet
D. all the above
12
200State whether true or false.
Magnetic lines of force are primarily curved lines.
A. True
B. False
12
201Which of the following best describes the field due to a magnet?
A. The region where its effects are felt
B. The two regions close to its poles
c. The region between its poles
D. The region where it aligns itself along the north-south direction
12
202When an iron cylinder of diameter ( 0.20 mathrm{cm} ) and length ( 30 mathrm{cm} ) is kept parallel to a magnetic field of intensity
( 4800 A / m ) the cylinder acquires a pole
strength of ( 9 A m . ) Find the permeability
of the material of the rod?
A ( .0 .075222 times 10^{-4} mathrm{H} / mathrm{m} )
B . ( 9.522 times 10^{-4} mathrm{H} / mathrm{m} )
c. ( 75.22 times 10^{-4} mathrm{H} / mathrm{m} )
D. ( 7.522 times 10^{-4} mathrm{H} / mathrm{m} )
12
203A thin diamagnetic rod is placed vertically between the poles of an electromagnet. When the current in the electromagnet is switched on, then the diamagnetic rod is pushed up, out of the horizontal magnetic field. Hence the rod gains gravitational potential energy. The work required to do this comes
from
A. The lattice structure of the material of the rod
B. The current source
c. The induced electric field due to the changing magnetic field
D. The magnetic field
12
204The material used for permanent
magnet has:
A. low retentivity, high coercivity
B. high retentivity, low coercivity
c. high retentivity, high coercivity
D. low retentivity, , low coercivity
12
205Which of the following cannot be ferromagnetic?

This question has multiple correct options
A . alloys
B. solids
c. liquids
D. gases

12
206A dip needle lies initially in the magnetic meridian when it shows an angle of dip ( theta ) at a place. The dip circle
is rotated through an angle ( x ) in the
horizontal plane and then it shows an angle of ( operatorname{dip} theta ) ‘. Then ( frac{tan theta^{prime}}{tan theta} ) is
A ( cdot frac{1}{cos x} )
B. ( frac{1}{sin x} )
c. ( frac{1}{tan x} )
D. ( cos x )
12
207The value of magnetic susceptibility for para-magnetic substance is
A . infinity
B. low positive
c. low negative
D. zero
12
208Two like magnetic poles of strength 10 and ( 40 S I ) units are separated by a
distance ( 30 c m . ) The intensity of magnetic field is Zero on the line joining them.
A. At a point ( 10 mathrm{cm} ) from stonger pole.
B. At a point ( 20 mathrm{cm} ) from stonger pole.
c. At a mid-point.
D. At infinity.
12
209A rectangle with its dimensions is as shown. A Magnetic mono pole of pole strength ‘ ( mathrm{m}^{prime} ) is placed at the point ( ^{prime} mathrm{A}^{prime} ) and another pole of pole strength ‘5m’ is
placed at the point ‘B’. The magnetic force acting between them is ‘F’.’ If magnetic pole at the point ‘B’ is moved to the point ‘C’, Find final magnetic force acting between them.
A ( cdot frac{F}{10} )
в. ( frac{F}{17} )
( c cdot frac{F}{20} )
( mathbf{D} cdot F )
12
210Magnetic field can be defined as the:
A. space surrounding the magnet in which magnetic force acts
B. space surrounding the magnet in which electric force acts
C. space surrounding the magnet in which no force acts
D. none
12
211A dip needle shows an angle of dip ( theta ) in a place which is in the magnetic meridian. Now, the dip circle is rotated through an angle ( x ) in the horizontal plane and then it
shows an angle of dip ( theta_{1} . ) Value of
( tan theta_{1} / tan theta ) is :
A ( cdot frac{1}{cos x} )
B. ( frac{1}{sin x} )
c. ( frac{1}{tan x} )
D. ( cos x )
12
212Define magnetic inclination or angle of
dip.
12
213Choose the correct option which describe the magnetic field produced by a current in a long, straight wire?
A. The field in uniform
B. The field increases in strength as the distance from the wire increases
c. The field lines are directed parallel to the wire, but opposite to the direction of the current
D. The field lines are directed radially outward from the wire
E. The field lines form circles about the wire
12
214Lines of force
A. are not imaginary lines
B. cannot be mapped on paper
c. do not intersect each other
D. always intersect each other
12
215Two short magnets with pole strengths of
( 900 A m ) and ( 100 A m ) are placed with their
axes in the same vertical line, with
similar poles facing each other. Each magnet has a length of ( 1 mathrm{cm} ). When
separation between the nearer poles is
( 1 mathrm{cm}, ) the weight of the upper magnet is
supported by the repulsive force between the magnets. If ( g=10 m s^{-2} ), then the
mass of upper magnet is ( left(x times 10^{-4}right) )
A. ( 1.6 k g )
в. ( 2.4 k g )
c. ( 5.5 k g )
D. ( 4.8 k g )
12
216A point near the equator has:
( mathbf{A} cdot B_{V}>>B_{H} )
( mathbf{B} cdot B_{H}>>B_{V} )
( mathbf{c} cdot B_{V}=B_{H} )
D ( . B_{V}=B_{H}=0 )
12
217In the given figure, the electron enters into the magnetic field. It deflects in ( x ) direction

Two parallel beams of electrons moving in the same direction produce a mutual force
( A cdot+ ) ve ( X ) direction
B. – ve X direction
c. ( + ) ve ( Y ) direction
D. – ve Y direction

12
218What are magnetic field lines? How is the direction of magnetic field at a
point in a magnetic field determined using field lines?
12
219At the magnetic north pole of the earth,
the value of the horizontal component of earth’s magnetic field and angle of dip are respectively.
A. zero, maximum
B. maximum,minimum
c. maximum,maximum
D. minimum,minimum
12
220Classify the following materials with regard to magnetism:
Manganese, Cobalt, Nickel, Bismuth,
Oxygen and Copper
12
221Core of electromagnets are made of ferromagnetic material which has:
A. High permeability and Low retentivity
B. High permeability and High retentivity
c. Low permeability and High retentivity
D. Low permeability and Low retentivitty
12
22235. A magnet is suspended in such a way that it oscillates in
the horizontal plane. It makes 20 oscillations per minute
at a plane where dip angle is 30° and 15 oscillations per
minute at a place where dip angle is 60°. The ratio of
earth’s magnetic field at two places is
(a) 3v3:8
(b) 16:9 V3
(c) 4:9
(d) 2V2:3
12
223The substances which are attracted
towards a magnet are called
A. metals
B. ferro-magnetic materialss
c. non-metals
D. dia-magnetic materials
12
224If ( M_{2}= ) magnetization of a
paramagnetic sample, ( mathrm{B}= ) external magnetic field, ( T= ) absolute temperature, ( C= ) curie constant then according to Curie’s law in magnetism, the correct relation is
A ( cdot M_{z}=frac{T}{C B} )
В. ( quad M_{z}=frac{C B}{T} )
( ^{mathrm{c}} cdot_{C}=frac{M_{z}}{T} )
D. ( _{C}=frac{T^{2}}{M_{z} B} )
12
225A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its North tip pointing down at ( 22^{0} ) with the horizontal. the
horizontal component of the earth’s magnetic field at the place is known to be 0.35 G.The magnitude of the earth’s magnetic field at the place will be:-
A . 0.68 G
B. 0.36 G
( c cdot 0.83 G )
D. 0.86 G
12
226Which of the following independent quantities is not used to specify the
earth’s magnetic field.?
A. Magnetic declination ( (theta) )
B. Magnetic dip.
C. Horizontal component of earth’s field ( left(B_{H}right) )
D. Vertical component of earth’s field ( left(B_{V}right) )
12
227Assertion
At high temperature, a ferromagnet
becomes a paramagnet.
Reason
The ferromagnetic property depends on
temperature.
A. Both Assertion and Reason are correct and Reason is
the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
228A strong magnetic field is applied on a stationary electron. Then
A. the electron moves in the direction of the field
B. the electron moves in an opposite
c. the electron remains stationary
D. the electron starts spinning
12
229Magnetic force required to demagnetize the material
A. retainity
B. coercivity
c. energy loss
D. hysteresis
12
230Show diagrammatically the behaviour
of magnetic field lines in the presence of
(i) paramagnetic and
(ii) diamagnetic substances. How does one explain this distinguishing feature?
12
231A strong bar magnet placed vertically above a horizontal wooden board. The
magnetic lines of force will be
A. only in horizontal plane around the magnet
B. only in vertical plane around it magnet.
c. in horizontal as well as vertical plane around the magnet
D. in all the planes around the magnet
12
232Assertion
Magnetic force between two short
magnets, when they are co-axial follows
inverse square law of distance.
Reason
The magnetic forces between two poles
do not follow inverse square law of
distance.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.
12
233At a place, the horizontal and vertical components of earth’s magnetic field are equal. What is the angle of dip at that place?
A . 45
B. 55
( c cdot 65 )
D. 76
12
234The angle of dip at a place on the earth
gives:
A. The horizontal component of the earth’s magnetic field.
B. The location of geograhical meridian.
C. The vertical component of the earth’s magnetic field.
D. The direction of the earth’s magnetic field.
12
235If the magnetic moment of magnet is ( 0.8 times 10^{-3} A m^{2} ) and the force acting on
each pole in a uniform magnetic field strength of 0.48 gauss, is ( 0.512 times 10^{-6} N )
The distance between the poles of the magnet is : (in ( c m) )
A . 25
в. 12.5
c. 15
D. 7.5
12
236A particle of mass ( m ) and positive
charge ( boldsymbol{q}, ) moving with a uniform
velocity ( v, ) enters a magnetic field ( B ) as
shown in figure.
(a) Find the radius of the circular arc it
describes in the magnetic field
(b) Find the angle subtended by the arc
at the centre
(c) How long does the particles stay inside the magnetic field?
(d) Solve the three parts of the above
problems if the charge ( q ) on the particle is negative then.
12
237A short bar magnet has a magnetic moment of ( 0.48 J T^{-1} . ) Give
the direction and magnitude of the magnetic field produced by the magnet at a distance of ( 10 mathrm{cm} ) from the
centre of the magnet on
(a) the axis, (b) the equatorial lines (normal bisector) of
the magnet
12
238The value of susceptibility for super
conductor is
( A cdot O )
( B . infty )
( mathbf{C} cdot+1 )
D. – –
12
239Three identical specimens of a magnetic materials nickel, antimony and aluminium are kept in a nonuniform magnetic field. Draw the modification in the field line in each
case. Justify your answer.
12
240The permanent magnetic moment of atoms or molecules of a diamagnetic
material is
A. small
B. large
c. negative
D. zero
12
241Magnetic lines of force are:
A. continuous
B. discontinuous
c. some times continuous and some times discontinuous
D. nothing can be said
12
242A small rod of bismuth is suspended
freely between the poles of a strong magnet. It is found to arrange itself at right angles to the magnetic field. What is established by the observation?
12
243If a magnet of pole strength ( mathrm{m} ) is divided into four parts such that the length and width of each part is half that of the
initial one, then the pole strength of each
part will be
( A cdot m / 4 )
B. m/2
( c cdot m / 8 )
D. ( 4 mathrm{m} )
12
24467. The dipole moment of each molecule of a parama
gas is 1.5 x 10-4 A x mʻ. The temperature of a
27°C and the number of molecules per unit volume
it is 2 x 1026 m . The maximum possible intensity of
magnetisation in the gas will be
(a) 3 x 10° A/m (b) 4 x 10-‘A/m
(c) 5 x 10° A/m
(d) 6 x 104 A/m
12
245The angle of dip at a certain place where the horizontal and vertical components of the earth’s magnetic field are equal
is?
A ( .30^{circ} )
B . ( 75^{circ} )
( c cdot 60^{circ} )
D. ( 45^{circ} )
12
246The magnetic field intensity due to a magnet is ( frac{100}{4 pi} mathrm{A} / mathrm{m} ). The induction field strength due to it is :
( mathbf{A} cdot 1 times 10^{-5} T )
в. ( frac{4 pi}{10^{3}} T )
c. ( frac{10^{3}}{4 pi} times 100 T )
D. ( frac{10^{-5}}{4 pi} T )
12
247Angle of dip at a place is ( 60^{0} ) and earth’s magnetic field is ( 8 mu T . ) Its horizontal
component ( boldsymbol{B}_{boldsymbol{H}} ) is :
A ( .4 sqrt{3 mu} T )
в. ( 4 mu T )
c. ( frac{8}{sqrt{3}} mu T )
D. ( 8 sqrt{3 mu} T )
12
248Two short bar magnets with magnetic moments 400 ab ( A c m^{2} ) and ( 800 a b A )
( c m^{2} ) are placed with their axis in the same straight line with similar poles facing each other and with their centres
at ( 20 mathrm{cm} ) apart from each other. Then
the force of repulsion is:
Disclaimer: No option as 0.08 dyne was
given in the original paper.
A. 12 dyne
B. 6 dyne
c. 0.08 dyne
D. 150 dyne
12
249Force between two identical bar magnets
whose centres are rmeters apart is ( 4.8 N )
when their axis are in the same line. If the
separation is increased to ( 2 r ) meters, the force between them is reduced to:
A. 2.4
B. 1.2 N
c. ( 0.6 mathrm{N} )
D. 0.3 N
12
250When the atomic magnetic moments
are randomly oriented in a solid its magnetic behavior is termed as
A. semi-magnetic.
B. anti-ferromagnetic
C. paramagnetic.
D. poly crystalline.
12
251The hysteresis cycle curve for the
material of a permanent magnet is:
A. short and wide
B. tall and narrow
c. tall and wide
D. short and narrow
12
252Curie-Weiss law is obeyed by iron:
A. at Curie temperature only.
B. at all temperatures.
C . below Curie temperature.
D. above Curie temperature.
12
253Assertion: When diamagnetic material is placed in a non-uniform magnetic field, it tends to move from stronger to
the weaker part of the magnetic field. Reason : Diamagnetic materials possess strong magnetism.
A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true and reason is not the correct explanation of assertion.
c. If assertion is true but reason is false
D. If both assertion and reason are false
12
254The strength of the magnetic field
around a straight conductor:
A. is same everywhere around the conductor
B. obeys inverse square law
C. is directly proportional to the square of the distance from the conductor
D. none of these
12
255Assertion(A): If one arm of a ( U ) -tube
containing a diamagnetic solution is placed in between the poles of a strong magnet with the level in line with the
field, the level of the solution falls Reason(R): Diamagnetic substances are repelled by the magnetic field
A. both ( A, R ) are true and ( R ) is the correct explanation of
B. both A,R are true and R is not correct explanation of A
c. A is true, R is false
D. A is false R is true
12
256At magnetic poles, the angle of dip is
A ( cdot 45^{circ} )
B . ( 30^{circ} )
c. zero
D. ( 90^{circ} )
12
257The hysteresis cycle for the material of a transformer core is?
A. Short and wide
B. Tall and narrow
c. Tall and wide
D. short and narrow
12
258Curie temperature is the temperature
above which
A. a ferromagnetic material becomes paramagnetic
B. a paramagnetic material becomes diamagnetic
C . a ferromagnetic material becomes diamagnetic
D. a paramagnetic material becomes ferromagnetic
12
25919 The variation of magnetic susceptibility (W) with
magnetising field for a paramagnetic substance is
(+) f
(b)
+ O Exo
lor
(d)
TH
18The unrintion of magnetic susceptibility (y) with absolute
12
260Distinguish between ‘paramagnetic’ and ‘ferromagnetic’ substances.12
261Magnetic equator is
A. Isoclinic line
B. Aclinic line
C. Isogonic line
D. Agonic line
12
262State True or False.
Magnetic lines of force do not intersect
A. True
B. False
12
263Which metal is used to make
ferromagnets?
A. Iron
B. cobalt
c. Nickel
D. All of these
12
264Magnetic susceptibility ( chi ) of a paramagnetic material changes with
absolute temperature ( T ) as
A ( cdot chi propto T^{-1} )
B. ( x= ) constant
c. ( chi propto e^{r} )
D. ( chi propto T )
12
265The horizontal component of earth’s magnetic field at a certain place is ( 3.0 times 10^{-5} mathrm{T} ) and having a direction
from the geographic south to geographic north. The force per unit length on a very long straight conductor carrying a steady current of ( 1.2 mathrm{A} ) in east to west direction is then
A. ( 3.0 times 10^{-5} mathrm{N} mathrm{m}^{-1} )
В. ( 3.2 times 10^{-5} mathrm{N} mathrm{m}^{-1} )
c. ( 3.6 times 10^{-5} mathrm{N} mathrm{m}^{-1} )
D. ( 3.8 times 10^{-5} mathrm{N} mathrm{m}^{-1} )
12
266A bar magnet of magnetic moment
( 1.2 A m^{2} ) is placed in the magnetic
meridian with its south pole pointing the north. If a neutral point is found at a
distance of ( 20 mathrm{cm} ) from the centre of the
magnet, the value of the horizontal
component of the earth’s magnetic field is :
A. ( 3 times 10^{-5} T )
B. ( 3 times 10^{-4} T )
c. ( 3 times 10^{3} T )
D. ( 3 times 10^{-2} T )
12
267Assertion
Basic difference between an electric
line of force and magnetic lines of force is that former is discontinuous and the
latter is continuous or endless.
Reason
No electric lines of force exist inside a
charged body but magnetic lines do
exist inside a magnet.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Assertion is incorrect but Reason is correct
12
268A positively charged particle in a uniform magnetic field moves in a circular path in the clockwise direction,
parallel to the plane of the page. In what direction do the magnetic field lines point?
A. Out of the page
B. Into the page
c. To the left
D. To the right
E. In a clockwise pattern parallel to the plane of the page
12
269The relative permeability is represented
by ( mu_{r} ) and the susceptibility by ( chi ) for a magnetic substance. Then, for a paramagnetic substance. Then, for a paramagnetic substance
A ( cdot mu_{r}>1, chi>0 )
в. ( mu_{r}>1, chi1, chi>0 )
D. ( mu_{r}<1, chi<0 )
12
270Assertion: A soft iron core is used in a
moving coil galvanometer to increase the strength of magnetic field Reason: From soft iron more number of
the magnetic lines of force passes
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not correct explanation of
c. A is true, but R is false
D. A is false, but R is true
12
271The magnetic susceptibility of an ideal diamagnetic substance is
A . –
B.
( c cdot+1 )
( D cdot alpha )
12
272Which of the following is universal magnetic property.?
A. Ferromagnetism
B. Diamagnetism
c. Paramagnetism
D. Anti-ferromagnetism.
12
273If a magnet is suspended at an angle
( 30^{circ} ) to the magnetic meridian, the dip
needle makes an angle of ( 45^{circ} ) with the horizontal. The real dip is:
A ( cdot tan ^{-1}(sqrt{3 / 2}) )
B. ( tan ^{-1} sqrt{3} )
( ^{mathrm{c}} tan ^{-1}(sqrt{frac{2}{3}}) )
D ( cdot tan ^{-1}left(frac{2}{sqrt{3}}right) )
12
274The work done in rotating a bar magnet
of magnetic moment ( M ) from its unstable equilibrium position to its stable equilibrium position in a uniform magnetic field ( B ) is
( mathbf{A} cdot 2 M B )
в. ( M B )
c. ( -M B )
D. ( -2 M B )
12
275Assertion (A): Poles of a magnet can
never be separated Reason (R): Since, each atom of a
magnetic material is a magnet in itself
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not correct explanation of A
C. A is true, but R is false
D. A is false, but R is true
12
276The value of earth’s magnetic field can
be
A . ( 0.5 G )
в. ( 5 G )
( c cdot 10 G )
D. ( 50 G )
12
27744. A ferromagnetic material is heated above its
temperature. Which one is a correct statement?
(a) Ferromagnetic domains are perfectly arranged
(b) Ferromagnetic domains becomes random
(c) Ferromagnetic domains are not influenced
(d) Ferromagnetic material changes itself into diamagnetic
material
12
278Metals getting magnetised by orientation of atomic magnetic moments in external magnetic field are
called
A. diamagnetics
B. paramagnetics
c. ferromagnetics
D. antimagnetics
12
279Obtain an expression for magnetic flux density B at the centre of a circular coil of radius ( mathrm{R} ), having ( mathrm{N} ) turns and carrying
a current ( boldsymbol{I} )
12
280A straight wire lying in a horizontal plane carries a current from north to
south. What will be the direction of
magnetic field at a point just underneath it?
A. Towards north.
B. Towards east
c. Towards west
D. Towards south.
12
281In a vertical plane ( p_{1} ) making angle ( 30^{circ} ) with magnetic meridian, apparent
angle of dip in vertical plane ( p_{2} ) is ( 60^{circ} )
which is perpendicular to plane ( p_{1} ) is:
A ( .30^{circ} )
B . ( 45^{circ} )
( mathbf{c} cdot tan ^{-1}(3) )
D. ( tan ^{-1}left(frac{2}{3}right) )
12
282Curie temperature is the temperature
above which
A. a ferromagnetic material becomes paramagnetic
B. a paramagnetic material becomes diamagnetic
C . a ferromagnetic material becomes diamagnetic
D. a paramagnetic material becomes ferromagnetic.
12
283Dip circle is not set into magnetic meridian and the angle at which it is inclined to the magnetic meridian is
unknown. ( delta^{prime} ) and ( delta^{prime prime} ) are apparent dips at a place in which dip circle is kept in transverse positions. The dip is:
( mathbf{A} cdot cot delta=cot delta^{prime}+cos delta^{prime prime} )
B. ( tan ^{2} delta^{prime}=tan delta^{prime}+tan ^{2} delta^{prime prime} )
( mathbf{c} cdot cos ^{2} delta=cos ^{2} delta^{prime}+cos ^{2} delta^{prime prime} )
D. ( cot ^{2} delta=cot ^{2} delta^{prime}+cot ^{2} delta^{prime prime} )
12
28432. Two bar magnets when placed with their similar poles
together makes 20 vib/min. When one of them is reversed
the number of vibrations become 15 vib/min. What is the
ratio of their dipole moment?
(a) 7:45
(b) 25:7
(c) 1:4
(d) 4:1
util
ihimmerid
22
an
12
285Write definition of Curie temperature for ferromagnetic substance.12
286A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip pointing
down at ( 22^{0} ) with the horizontal. The
horizontal component of the earth’s magnetic field at the place is known to be ( 0.35 G . ) Determine the magnitude of
the earth’s magnetic field at the place.
A . 0.12
B. 1.23
( c cdot 4.56 )
D. 0.38
12
287Due to a small magnet, intensity at a distance ( x ) in the end on position is 9 gauss. What will be the intensity at a distance ( frac{x}{2} ) on broad side on position.
A. 9 gauss
B. 4 gauss
c. 36 gauss
D. 4.5 gauss
12
288What are magnetic field lines with the properties give direction of magnetic field for a point and an electric dipole12
28941. Among the following properties describing diamagnetic
identify the property that is wrongly stated.
(a) Diamagnetic material do not have permanent magneti
moment
(b) Diamagnetism is explained in terms of electromagnetic
induction
(c) Diamagnetic materials have a small positive
susceptibility
(d) The magnetic moment of individual electrons
neutralize each other
12
290Assertion: Substances which at room
temperature retain their ferromagnetic
property for a long period of time are
called permanent magnets.

Reason: Permanent magnet can be
made by placing a ferromagnetic rod in
a solenoid and passing current through
¡t.
A. If both assertion and reason are true and reason is the
correct explanation of assertion.
B. If both assertion and reason are true and reason is not the correct explanation of assertion.
C. If assertion is true but reason is false.
D. If both assertion and reason are false.

12
291Write three properties of ferromagnetic
materials.
12
292In a long hollow vertical metal pipe a magnet is dropped. During its fall, the acceleration of magnet
A. will decrease linearly
B. will decrease upto a value which is less than ( g ).
c. will decrease to zero and will attain a terminal speed
D. may increase or decrease
12
293A electron experiences a force ( (4.0 hat{i}+ ) ( mathbf{3} . mathbf{0} hat{boldsymbol{j}}) times mathbf{1 0}^{-mathbf{1 3}} boldsymbol{N} ) in a uniform magnetic
field when its velocity is ( 2.5 hat{k} times ) ( 10^{7} m s^{-1} . ) The magnetic field vector ( vec{B} )
is
( mathbf{A} cdot-0.075 hat{i}+0.1 hat{j} )
B. ( 0.1 hat{i}+0.075 hat{j} )
c. ( -0.075 hat{i}-0.1 hat{j}+hat{k} )
D. ( -0.075 hat{i}-0.1 )
12
294Two coils each of 100 turns are held
such that one lies in vertical plane and the other in the horizontal plane with
their centers coinciding. The radius of
the vertical coil is ( 0.20 m ) and that of the
horizontal coil is 0.30 m. How will you
neutralize the magnetic field of the earth at their common center? If the
summation of current to be passed
through each coil is ( i_{text {total}}=x A . ) Find
( x^{*} 10 )
Horizontal component of earth’s magnetic field ( =0.35 times 10^{-4} T ) and
angle of ( operatorname{dip}=30^{circ} )
12
295A line joining places of zero dip is called
A . aclinic
B. isoclinic
c. isodynamic
D. isogonal
12
296The magnetising field required to be applied in opposite direction to reduce residual magnetism to zero is called
A. coercivity
B. retentivity
c. hysteresis
D. none of these
12
297A straight wire carries conventional
current toward the sky. What is the direction of the magnetic
field due to the current west of the wire?
A. North
B. South
c. East
D. west
E. Up
12
298Materials suitable for permanent
magnet, must have which of the
following properties?
A. High retentivity, low coercivity and high permeability
B. Low retentivity, low coercivity and low permeability
c. Low retentivity, high coercivity and low permeability
D. High retentivity, high coercivity and high permeability
12
299A jet plane having a wing-span of ( 25 mathrm{m} ) is travelling horizontally towards east with a speed of ( 3600 mathrm{km} / ) hour. If the Earth’s magnetic field at the location is
( 4 times 10^{-4} mathrm{T} ) and the angle of dip is ( 30^{circ} )
then, the potential difference between
the ends of the wing is?
A. ( 4 mathrm{v} )
B. 5 v
( c cdot 2 v )
D. 2.5
12
300A small magnet is suspended by a silk thread from a rigid support such that the magnet can freely swing. Describe its behaviour.12
301Answer the question in at least 50
words.

Give the characteristic of magnetic
field lines.

12
302What happens to ferromagnetic substance heated above Curie
temperature?
12
303A short bar magnet of moment ( 3.2 A m^{2} )
lies in magnetic meridian with its north pole pointing north. A neutral point is
obtained at a distance of ( 20 mathrm{cm} ) from the
centre of the magnet. Find the horizontal.
12
304Which of the following is correct about the earth’s magnetic field?
A. Earth’s magnetic field is nearly dipolar
B. It is approximately aligned with earth’s rotation axis
c. It spontaneously reverses every 200,000 years
D. All of these
12
305What are diamagnetic substances?12
306Current of ( 2 A ) passing through a coil of
100 turns gives rise to a magnetic flux of ( 5 times 10^{-3} W b ) per turn. The magnetic energy associated with coil is
( mathbf{A} cdot 5 times 10^{-3} J )
B. 5.5
c. ( 0.5 times 10^{-3} J )
D. ( 0.5 J )
12
307Derive expression for the intensity of magnetic field at a point in end on position due to a short bar magnet12
308Which of the following shows that the earth behaves as a magnet?
A. Repulsion between like poles
B. Attraction between unlike poles
C. Existence of null points in the magnetic field of a bar magnet
D. Non existence of monopoles
12
309At Curie temperature the ferromagnetic materials get converted into.
A. non-magnetic material
B. para magnetic material.
c. dia magnetic material.
D. all of the above.
12
310If the magnetizing field on a ferromagnetic material is increased, its permeability
A . Decreased
B. Increased
c. Is unaffected
D. May be increased or decreased
12
311A paramagnet magnet behaves like a solenoid because both contain currents
in the form of
A. Circles
B. Parabola
c. Straight line
D. Ellipse
12
312On applying an external magnetic field, to a ferromagnetic substance domains.
A. Align in the direction of magnetic field.
B. Align in the direction opposite to magnetic field
c. Remain unaffected
D. align randomly
12
313The diagram shows two magnets and
two iron rods placed in a line.

Which magnetic poles are induced at the ends ( J ) and ( K ) of the iron rods?
A. Pole induced at end ( J-N ), pole induced at end ( K-N )
B. Pole induced at end ( J-N ), pole induced at end ( K-S )
C. Pole induced at end ( J-S ), pole induced at end ( K-N )
D. Pole induced at end ( J-S ), pole induced at end ( K-S )

12
314The magnetic field produced by a current carrying solenoid is similar to the magnetic field produced by a bar
magnet.
12
315Mark the correct set of ferromagnetic substances
A. iron, cobalt and nickel
B. iron, copper and lead
c. silicon, bismuth and nickel
D. aluminium, sodium and copper.
12
316If horizontal and vertical components of the earth’s magnetic field are equal at a certain place, then the angle of the dip at that place will be
A ( cdot 90^{circ} )
B. ( 60^{circ} )
( c cdot 45^{circ} )
D. ( 0^{circ} )
12
317Two point charges in air at a distance
of ( 20 c m . ) from each other interact with a
certain force. At what distance from
each other should these charges be placed in oil of relative permittivity 5 to obtain the same force of interaction
A. ( 8.94 times 10^{-2} mathrm{m} )
В. ( 0.894 times 10^{-2} mathrm{m} )
( c cdot 89.4 times 10^{-2} m )
D. ( 8.94 times 10^{2} m )
12
318Liquids and gases never exhibit
A. diamagnetic properties
B. para magnetic properties
C . ferro magnetic properties
D. electro magnetic properties
12
319If the distance between two unlike poles is doubled then the force of attraction
between them becomes
times its original value.
A ( cdot frac{1}{2} )
B. ( frac{1}{4} )
( c cdot 2 )
D. 4
12
320The area enclosed by a hysteresis loop is a measure of
A. retentivity
B. susceptibility
c. permeability
D. energy loss per cycle
12
321The energy band gap of a superconductor formed near the critical
temperature is due to
A. the exponential decrease in heat capacity
B. the exponential increase in heat capacity
c. the gradually decrease in heat capacity
D. the gradually increase in heat capacity
12
322What are the different elements of
earth’s magnetism? What is the relation between them?
12
323Consider the following statements:
(i) Soft iron conducts electricity
(ii) Soft iron is magnetic material
(iii) Soft iron is used for magnetic
permanent magnets
(iv) Soft iron is used as electro magnet
A. (i) and (ii) are correct
B. (i) and (iii) are correct
c. (ii) and (iv) are correct
D. (i), (ii) and (iv) are correct
12
324The magnetic field of the earth can be modelled by that of a point dipole placed at the centre of the earth. The
dipole axis makes an angle of ( 11.3^{circ} )
with the axis of the earth. At Mumbai,
declination is nearly zero. Then,
A. The declination varies between ( 11.3^{circ} mathrm{W} ) to ( 11.3^{circ} mathrm{E} )
B. The least declination is ( 0^{circ} )
C. The plane defined by dipole axis and the earth axis passes through Greenwich
D. Declination averaged over the earth must be always negative
12
325Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature
then it will show
A. diamagnetism
B. paramagnetism
c. anti ferromagnetism
D. no magnetic property
12
326The most important features of
superconductor is that
A. once current is set up in a superconductor ring, it will continue indefinitely even if the battery is off
B. it has high efficiency compared to other conductors
C. it can pass maximum no of electrons when current is passed through it.
D. none of the above
12
327State any two properties of magnetic lines of force.12
328Iron loses magnetic property at:
A. melting point
В. ( 1000 K )
C . curie point
D. boiling point
12
329Two identical bar magnets are held perpendicular to each other with a certain separation, as shown below. The
area around the magnets is divided into
four zones. Given that there is a neutral
point it is located in.
A. Zone I
B. Zone II
C. Zone III
D. Zone IV
12
330A dip needle shows angle of dip ( theta ) when
the dip circle is placed in magnetic meridian. Now, the dip circle is rotated
by an angle ( alpha ) and the apparent angle of
dip at this place is ( theta^{prime} ), then
( left(tan theta^{prime} / tan thetaright) ) is :
A . ( 1 / cos alpha )
B. ( 1 / sin alpha )
( c cdot cos alpha )
D. sina
12
33160. Figure shows a short magnet executing small oscillations
in a vibration magnetometer in earth’s magnetic field
having horizontal component w
24 u T. The period of oscillation is
0.1 s. When the key K is closed, an
upward current of 18 A is established
as shown. The new time period is
(a) 0.1 s
(b) 0.2 s
(c) 0.3 s
(d) 0.4 s
11
0.2
m
12
332The critical temperature for
superconductors is the temperature at which the electrical resistivity of a
metal
A. drops to zero
B. increase to maximum limit
c. decrease to a certain limit
D. none of the above
12
333For soft iron, in comparison with steel:
A. hysteresis loss is more
B. hysteresis loss is same
C. hysteresis loss is less
D. hysteresis loss is negligible
12
334The value of Curie temperature for ( N i ) is
nearly
( mathbf{A} cdot 631 K )
B. ( 770 K )
( mathbf{c} .890 K )
D. ( 1100 K )
12
335What we have learnt about heating
effect of electric current. In studied
about magnets and magnetic lines of force
12
336The figure gives experimentally measured B vs. H variation in a
ferromagnetic material. The retentivity
co-ercivity and saturation, respectively, of the material are :
A. ( 1.5 T, 50 A / m ) and 1.07
B. ( 150 A / m, 1.0 T ) and ( 1.5 T )
c. ( 1.5 T, 50 A / m ) and 1.07
D. ( 1.0 T, 50 A / m ) and 1.57
12
33751. If a magnetic substance is kept in a magnetic field, then
which of the following is thrown out?
(a) Paramagnetic (b) Ferromagnetic
(c) Diamagnetic (d) Antiferromagnetic
12
338What is ( mu_{max } ) equal to?
A ( cdot mu_{max } approx 1.0 times 10^{4} )
B . ( mu_{max } approx 2.0 times 10^{4} )
C ( cdot mu_{max } approx 1.0 times 10^{3} )
D. ( mu_{max } approx 2.0 times 10^{3} )
12
339The correct value of dip angle at a place is
( 45^{circ} . ) If the dip circle is rotated by ( 45^{circ} ) out of the meridian, then the tangent of the
angle of apparent dip at the place is :
A .
в. 0.5
c. ( frac{1}{sqrt{2}} )
D. ( sqrt{2} )
12
340Alloys of ferromagnetic
materials
A. are always ferromagnetic in nature
B. need not be ferromagnetic in nature
C . are always diamagnetic in nature
D. are always antiferromagnetic in nature
12
341The magnetising field required to be applied in opposite direction to reduce residual magnetism to zero is called
A. retentivity
B. coercivity
c. hysteresis
D. flux
12
342The resultant magnetic field at the center of a bar magnet is zero.
A. True
B. False
12
343At a place, the angle of dip is ( 30^{0} . ) If the horizontal component of earth’s field is
( B_{H}, ) then the net field intensity at the place will be :
A ( cdot frac{B_{H}}{2} )
в. ( frac{2 B_{H}}{sqrt{3}} )
c. ( B_{H} sqrt{2} )
D. ( B_{H} sqrt{3} )
12
344The angle of dip at equator is
( mathbf{A} cdot 0^{circ} )
В . ( 45^{circ} )
( c cdot 60^{circ} )
D. ( 90^{circ} )
12
345Two magnetic poles of strengths ( 40 A m ) and ( 10 A m ) are separated by a distance
of ( 20 mathrm{cm} ) in air. The force between them
if the distance is reduced to ( 10 mathrm{cm} ) is
A ( cdot 4 times 10^{-3} N, 10^{-3} N )
B . ( 10^{-3} N, 4 times 10^{-3} N )
c. ( 2 times 10^{-3} N, 10^{-3} N )
D. ( 10^{-3} N, 2 times 10^{-3} N )
12
346A rectangle has sides of lengths ( 6 mathrm{cm} )
and ( 8 c m . ) Two magnetic poles each of
pole strength ‘ ( m ) ‘ are placed at the ends of one side of smaller length and magnetic force acting between them is
( F^{prime} . ) If they are moved to new positions of same rectangle so that they are diagonally opposite. Find the final force acting on each pole.
12
347The angle of dip increases as we move from
A. Poles to equator
B. Equator to poles
c. Dip is equal at all places
D. None of these
12
348The isoclinic lines on magnetic map
represent lines of
A. zero dip
B. equal declination
c. equal dip
D. equal horizontal field
12
349Two south poles each of pole strength 16 A m are placed at corners ( P, R ) of a square PQRS. The pole that should
placed at ‘Q’ to make S as null point is :
A. South pole of pole strength 32 A m
B. South pole of pole strength ( 32 sqrt{2} ) A ( m )
c. North pole of pole strength 32 A m
D. North pole of pole strength ( 32 sqrt{2} ) A ( m )
12
350Two straight infinitely long and thin parallel wires are spaced ( 0.1 mathrm{m} ) apart and carry a current of 10 ampere each. Find the magnetic field at a point distant ( 0.1 mathrm{m} ) from both wires in the two
cases when the currents are in the :
1) Same and
2) Opposite direction.
12
351The magnetic field due to a current
carrying loop of radius ( 12 mathrm{cm} ) at its
centre is ( 0.5 times 10^{-4} ) T. Find the
magnetic field due to the loop at an axial point ( 5 mathrm{cm} ) away from the centre.
12
35224. The correct value of dip at a place is 45°. If the dip circle 15
rotated 45° out of the magnetic meridian then the tangent
of the angle of the apparent dip is
(a) 1
(b)
(c)
2
12
353The ( _{–}-_{-}-_{-}- ) drawn at any point on the magnetic lines of force gives direction of magnetic field at that point.
A. tangent
B. perpendicular
c. chord
D. None
12
354Curie temperature is the temperature
above which
A. a ferromagnetic material becomes paramagnetic
B. a paramagnetic material becomes diamagnetic
C . a ferromagnetic material becomes diamagnetic
D. a paramagnetic material becomes ferromagnetic
12
355Which of the following is not a property of magnetic lines of force?
A. They neither have origin nor end.
B. These lines do not intersect
c. outside the magnet their direction is from north pole to south pole and inside the magnet these are from south to north pole.
D. None
12
356Define magnetic ‘declination’ and ‘dip’
at a place
12
357What is the value of magnetic potential,
at a distance of ( 1 mathrm{cm} ) from the pole, of
pole strength 60 A-m?
A. ( 600 mathrm{m} ) J/Am
B. 600 ( mu ) /Ат
c. 600 MJ/Am
D. 600 KJ/Am
12
358The shortest distance joining the magnetic poles of a magnet is known as magnetic length.
A. True
B. False
12
359Find at what height ( x_{m}, ) the ball will experience the maximum attraction.
A ( cdot x_{m}=frac{1}{sqrt{a}} )
B. ( x_{m}=frac{1}{sqrt{4 a}} )
c. ( _{x_{m}}=frac{1}{sqrt{2 a}} )
D. ( x_{m}=frac{2}{sqrt{a}} )
12
360A frog can be levitated in a magnetic field produced by a current in a vertical solenoid placed below the frog. This is possible because the body of the frog behaves as:
A. paramagnetic
B. diamagnetic
c. ferromagnetic
D. antiferromagnetic
12
361A powerful magnet attracts
A. all materials.
B. only ferromagnetic materials and their ores.
C. some materials and repels some other materials.
D. only iron and its ores but does not repel any material.
12
362The inherent property of all materials is
A. Diamagnetism
B. Paramagnetism
C. Ferromagnetism
D. Both a and
12
363Is there anything that can block the effects or decrease the effect of gravity? Any experiments that tested it?

Magnetism can be blocked and why not gravity?

12
364When a superconductor is placed in a weak external magnetic field ( mathrm{H} ), and cooled below its transition temperature
A. the magnetic field is ejected
B. the magnetic field get magnetized
c. the magnetic field strength increased
D. none of the above
12
36545. The material of permanent magnet has
(a) high retentively, low coercively
(b) low retentively, high coercively
(c) low retentively, low coercively
(d) high retentively, high coercively
12
366For a paramagnetic material, the dependence of the magnetic susceptibility ( chi ) on the absolute
temperature T is given by
A ( cdot x alpha T )
B. ( chi alpha ) constant ( times T )
c. ( chi alpha frac{1}{T} )
D. ( x= ) constant
12
367Which of the following are best suited to make the core of a transformer?
A. soft iron
B. steel
c. alnico
D. none of these
12
368The fields due to a bar magnet at equal distance on its axial and equatorial lines are
A. Equal to each other
B. The field on the axial line is double that on the equatorial line
c. The field on the equatorial line is double that on the axial line
D. There is no relationship between the two fields
12
369Where on the surface of the earth is the
vertical component of earth’s Magnetic field zero.
12
370The earth’s magnetic field at some place on magnetic equator of the earth is ( 0.5 times 10^{-4} ) T. Consider the radius of
the earth at that place as ( 6400 k m )
Then, magnetic dipole moment of the
earth is ( boldsymbol{A} boldsymbol{m}^{2} )
( left(mu_{0}=4 pi times 10^{-7} T m A^{-1}right) )
A ( cdot 1.31 times 10^{23} )
B. ( 1.05 times 10^{23} )
C. ( 1.15 times 10^{23} )
D. ( 1.62 times 10^{23} )
12
371The ratio of intensities of magnetic fields due to a short magnet in tan ( A )
and tan B position is
A .2:
B. 1: 2
( c cdot 3: )
( D cdot 1: 3 )
12
372Liquid oxygen remains suspended between two pole forces of a magnet because it is:
A. diamagnetic
B. paramagnetic
c. ferromagnetic
D. antiferromagnetic
12
373A telephone cable at a place has four long straight horizontal wires carrying a current of ( 1.0 mathrm{A} ) in the same direction
east to west. The earth’s magnetic field at the place is ( 0.39 mathrm{G} ), and the angle of dip is ( 35^{0} . ) The magnetic declination is nearly zero. What are the resultant
magnetic fields at point ( 4.0 mathrm{cm} ) below the cable?
B. 0.50 G
c. 1.25 G
D . 2.50 G
12
37434. A magnet is cut into four equal parts by cutting it parallel to
its length. What will be the time period of each part, if the
time period of the original magnet in the same field is To?
(b)
R$ +
(d) 4T,
12
375Assertion
When diamagnetic material is placed in a non-uniform magnetic field, it tends to move from stronger to the weaker part of the magnetic field.
Reason
Diamagnetic materials posses string magnetism.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
376Let the magnetic field on earth be modelled by that of a point magnetic dipole at the centre of earth. The angle of dip at a point on the geographical equator is
A. always zero
B. positive, negative or zero
c. unbounded
D. always negative
12
377A magnet makes 40 oscillations per minute at a place having magnetic field intensity of ( 0.1 times 10^{-5} ) T. At another place, it takes 2.5 seconds to complete one vibration. The value of earth’s
horizontal field at that place is
A . ( 0.25 times 10^{-6} mathrm{T} )
в. 0.36 ( times 10^{-6} ) т
c. ( 0.66 times 10^{-8} mathrm{T} )
D . 1.2 ( times 10^{-6} ) न
12
378The length of a magnet is large compared to its width and
breadth. The time period of its oscillation in an aberration
magnetometer is 2 s. The magnet is cut along its length
into three equal parts, which are then placed on each other
with their like poles together. The time period of this
combination will be
(a) 2 s
(b) 2/3 s
(c) 2/3 s
(d) 2/13 s (AIEEE 2004)
12
379Two isolated point poles of strength
( 30 A m^{2} ) and ( 60 A m^{2} ) are placed at a
distance of 0.3 m. The force of repulsion
is:
A ( cdot 2 times 10^{-3} N )
B . ( 2 times 10^{-4} N )
C ( .2 times 10^{5} N )
D. ( 2 times 10^{-5} N )
12
380The angle of dip at equator is :
A ( cdot 0^{circ} )
B . ( 45^{circ} )
( c cdot 60^{circ} )
D. ( 90^{circ} )
12
381Mark the incorrect statement.
A. The direction of the magnetic field is taken to be the direction in which a north pole of the compass needle moves inside it.
B. The magnetic field lines are closed curves.
C. No two field-lines are found to cross each other.
D. None
12
38225. The plane of dip circle is set in the geographic meridian
and the apparent dip is e. It is then set in a vertical plane
perpendicular to the geographic meridian. Now, the
apparent dipis ,. The angle of declination at that place is
(a) tan a = tane, tane,
(b) tana = (tane, )2 + (tan )
tane,
(c) tana =
tane
tane
(d) tana =
tane
12
383An electron moving along a horizontal line with respect to the observer and
towards the north. Due to each
magnetic field, it deflects towards the east then position observer:
A . In NHS
B. In SHS
c. At Equator
D. None
12
384A wire is bent in the form of an
equilateral triangle of side ( 100 mathrm{cm} ) and
carries a current of ( 2 A . ) It is placed in
the magnetic field of induction ( 2.0 T )
directed perpendicular to the plane of the paper. The direction and magnitude
of the magnetic force acting on each side of the triangle will be.
A. ( 2 N ) normal to the side towards centre of the triangle
B. ( 2 N ) normal to the side away from the centre of the triangle
c. ( 4 N ) normal to the side towards centre of the triangle
D. None of these
12
385The incorrect statement regarding the
lines of force of the magnetic field B is:
A. magnetic intensity is a measure of lines of force passing through unit area held normal to it.
B. magnetic lines of force form a closed curve.
C. inside a magnet, its magnetic lines of force move from north pole of a magnet towards its south pole.
D. magnetic lines of force never cut each other.
12
386A magnet is placed in earth’s magnetic field with south pole of the magnet
pointing north. At the neutral point This question has multiple correct options
A. The earth’s magnetic field is zero
B. The fields of the magnet and the earth are equal and in opposite direction
C. The magnet’s magnetic field is zero
D. The net magnetic field is zero
12
387Which of the following is represented by the area enclosed by a hysteresis loop
(B-H curve)?
A. Permeability
B. Retentivity
c. Heat energy lost per unit volume in the sample
D. susceptibility
12
388Which of the following does earth’s magnetic field deflect coming from outersphere?
A. Gas atoms
B. Radioactive isotopes
c. charged particles
D. Ozone molecules
12
389A conducting rod of length ( l ) and mass
( m ) is moving down a smooth inclined plane of inclination ( theta ) with constant
velocity ( v . A ) current ( i ) is flowing in the conductor in a direction perpendicular to paper inwards, a vertically upwards magnetic field ( B ) exists in space. Then
magnitude of magnetic field ( B ) is :
A. ( frac{m g}{i l} sin theta )
в. ( frac{m g}{i l} tan theta )
c. ( frac{m g cos theta}{i l} )
D. ( frac{m g}{text {ilsint}} )
12
390Two short magnets of equal dipole
moments ( M ) are fastened
perpendicularly at their centres as given in the figure. The magnitude of
the magnetic field at a distance ( d ) from
the centre on the bisector of the right angle is
A. ( frac{mu_{0} m}{4 pi d^{3}} )
в. ( frac{mu_{0} sqrt{2} M}{4 pi d^{3}} )
c. ( frac{mu_{0} 2 sqrt{2} M}{4 pi d^{3}} )
D. ( frac{mu_{0} 2 M}{4 pi d^{3}} )
12
39110 The x-1/T graph for an alloy of Y
paramagnetic nature is shown 0.4 —
in the figure. The curie constant 03
is, then
0.2
(a) 57 K
(b) 2.8 x 10-‘K
0.1
(c) 570 K
0 2 4 6 7
(d) 17.5 x 10-‘K
1/T(in 10-3 K-)
Which of the following is true
12
392A short bar magnet has a magnetic
moment of ( 0.65 mathrm{JT}^{-1} ), then the
magnitude and direction of the magnetic field produced by the magnet at a distance ( 8 mathrm{cm} ) from the centre of
magnet on the axis is:
A ( cdot 2.5 times 10^{-4} T, ) along NS direction
B . 2.5 times ( 10^{-4} T ), along SN direction
c. ( 4.5 times 10^{-4} T ), along NS direction
D. 4.5 times ( 10^{-4} T ), along SN direction
12
393Choose the correct statement about the
properties of magnetic lines of forces.
A. Lines of force are not imaginary lines
B. Lines of force cannot be mapped on paper
c. Lines of force do not intersect each other
D. Lines of force always intersect each other
12
394A wheel with 8 metallic spokes each 50
( mathrm{cm} ) long is rotated with a speed of 120 rev/min in a plane normal to the horizontal component of the Earth’s magnetic field. The Earth’s magnetic field at the place is ( 0.4 mathrm{G} ) and the angle
of ( 60^{circ} ).Calculate the emf induced
between the axle and the rim of the
wheel.How will the value of emf be
affected if the number of spokes were increased?
12
395Out of soft iron and steel which has
more coercivity, less retentivity.
A . iron
B. steel
c. both are equal
D. can’t say
12
396What are
¡) Magnetic declination
ii) Magnetic dip
iii) Horizontal component of earth’s
magnetic field at a place?
12
397Statement-1: The core of the transformer
is laminated to avoid loss of energy. Statement-2: A laminated metal sheet
placed in a changing magnetic field has
lower eddy current.
A. Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1.
B. Statement-! is true, statement-2 is false
c. Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement- –
D. Statement-1 is false, statement-2 is true
12
398A conductor behave as a super
conductor
A. Above critical temperature
B. At critical temperature
c. ( operatorname{At} 100^{circ} C )
D. At boiling point of that metal
12
399The magnetic field existing in a region is given by ( overrightarrow{boldsymbol{B}}=boldsymbol{B}_{0}left(1+frac{boldsymbol{x}}{boldsymbol{l}}right) hat{boldsymbol{k}} )
A square loop of edge I and carrying a
current i, is placed with its edges parallel to the ( X ) -Y axes, Find the magnitude of the net magnetic force experienced by the loop.
12
400A freely suspended magnetic needle will always come to rest in which direction?
A. north-east direction
B. north-west direction
c. north-south direction
D. south-west direction
12
401The angle between magnetic meridian
and geographical meridian is known as:
A. magnetic dip
B. magnetic latitude
C. magnetic declination
D. magnetic longitude
12
402Assertion
Magnetic force is always perpendicular to the magnetic field.
Reason
Electric force is along the direction of electric field.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion,
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
403A magnetic substance is kept in a magnetic field, it will be thrown out of the field if it is a
substance.
A. paramagnetic
B. ferromagnetic
c. diamagnetic
D. antiferromagnetic
12
404An electron having mass ‘ ( m ) ‘ charge ‘ ( q^{prime} ) and ( K . E . K ) enters a uniform magnetic
field – ‘ ( B ) ‘ perpendicularly. Then its frequency of rotation.
A ( cdot frac{q B}{pi m} )
в. ( frac{q B}{2 pi m} )
с. ( frac{q B E}{2 pi m} )
D. ( frac{q B}{2 pi} )
12
405The B-H curve (i) and (ii) shown in the
given figure is associated with
A . (i) diamagnetic and (ii) paramagnetic substance
B. (i) paramagnetic and (ii) ferromagnetic substance
( c . ) (i) soft iron (ii) stee
D. (i) steel and (ii) soft iron
12
406toppr 5
( Q ) туре уоиг question
and ( B_{2} ) (dashed line). If ( B_{2} ) is larger thar
( B_{1}, ) which of the following graphs shows
the correct variation of ( mathrm{R} ) and ( mathrm{T} ) in these
fields?
12
407The susceptibility of a diamagnetic substance is
( A cdot infty )
B. zero
c. small but negative
D. small but positive
12
408Which of the following is true regarding dimagnetic substances (symbols have their usual meaning)?
( mathbf{A} cdot mu_{r}>1, chi_{m}>1 )
B ( cdot mu_{r}>1, chi_{m}<1 )
( mathbf{c} cdot mu_{r}<1, chi_{m}<0 )
D. ( mu_{r}0 )
12
409At a certain location in Africa, compass
points ( 12^{circ} ) west of geographic north. The north tip of magnetic needle of a dip circle placed in the plane of magnetic
meridian points ( 60^{circ} ) above the horizontal. The horizontal component of earth’s field is measured to be ( 0.16 mathrm{G} )
The magnitude of earth’s field at the
location is?
A. 0.32 G
B. 0.42 G
c. ( 4.2 mathrm{G} )
D. 3.2G
12
410Core of electromagnets are made of ferromagnetic material which have
A. low permeability and low retentivity
B. high permeability and high retentivity
c. high permeability and low retentivity
D. low permeability and high retentivity
12
411A domain in ferromagnetic iron is in the
form of a cube of side length ( 2 mu m ) then
the number of iron atoms in the domain
are (Molecular mass of iron ( =mathbf{5 5 g} )
( m o l^{-1} ) and density ( =7.92 g c m^{-3} ) )
A ( cdot 6.92 times 10^{12} ) atoms
B. ( 6.92 times 10^{11} ) atoms
c. ( 6.92 times 10^{10} ) atoms
D. ( 6.92 times 10^{13} ) atoms
12
412State whether true or false.
Magnetic lines of force are imaginary lines.
A. True
B. False
12
413A diamagnetic substance produces a
A. Strong magnetic field in opposition of an externally applied magnetic field
B. Weak magnetic field in the direction of an externally applied magnetic field
C. Weak magnetic field in opposition of an externally applied magnetic field
D. Strong magnetic field in the direction of an externally applied magnetic field
12
414A N-pole of a very long magnetic needle is placed at a distance of ( 20 mathrm{cm} ) from a
point P. If the pole strength of the magnetic needle is ( 40 mathrm{Am} ), the magnetic induction at the point ( mathrm{P} ) is
( mathbf{A} cdot 10^{-3} mathbf{T} )
B . ( 10^{-4} mathrm{T} )
( mathbf{c} cdot 10^{-6} mathbf{T} )
D. ( 10^{-8} ) T
12
415If horizontal and vertical component of
earth’s magnetic field are equal to a certain place, the angle of dip is:
( A cdot 90^{circ} )
B . ( 45^{circ} )
( c cdot 60 )
( D cdot 0^{circ} )
12
416The narrowest hysterisis loop is for
A . cobalt stee
B. almico
c. soft magnetic material
D. stainless steel
12
417A rod of length L, along East west direction is dropped from a height H. If B
be the magnetic field due to earth at that place and angle of dip is ( theta ), then what is the magnitude of induced emf
across two ends of the rod when the rod
reaches the earth.
12
41854. Two ferromagnetic materials X and Y have hysteresis
curves of the shapes shown (see figure)
(a) X and Y are suitable for making a
permanent magnet as well as an
electromagnet
(b) X is more suitable for making a
permanent magnet while Y is more
suitable for making an electromagnet.
(c) X is more suitable for making an
electromagnet while Y is more suitable
for making a permanent magnet.
(d) neither X nor Y is suitable for making either a
permanent magnet or an electromagnet.
12
419Out of dia, para and ferromagnetism, the
universal property of all substances is
A. diamagnetism
B. paramagnetism
C. ferromagnetism
D. antiferromagnetism
12
420How are the field lines in a uniform
magnetic field ?
A . curved
B. parallel equidistant straight lines
c. parallel but non-equispaced straight lines
D. nothing can be said.
12
421Assertion
There are two neutral points on a horizontal board when a magnet is held vertically on the board
Reason
At the neutral point the net magnetic field due to the magnetic and magnetic field of the earth is zero
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
422The temperature bellow which a
material becomes a superconductor is called
A . critical temperature
B. absolute temperature
c. tripple point
D. none of the above
12
423A bar magnet of pole strength ( 20 A-m )
is cut into four equal parts breadth wise. Consider the following statements
A) Length becomes ( 1 / 4^{t h}, ) pole strength will be same. Intensity of magnetisation
will be same
B) Length becomes ( 1 / 4^{t h}, ) pole strength
will be ( 1 / 4^{t h} . ) Intensity of magnetisation
also becomes ( 1 / 4^{t h} )
A . A is correct
B. B is correct
c. Both A and B are correct
D. Both A and B are false
12
424If a particle of charge ( q ) is moving with velocity v along the z-axis and the magnetic field B is acting along ( mathbf{x} ) – axis, use the expression ( vec{F}=q(vec{v} times vec{B}) ) to
find the direction of the force ( F ) acting on it.
12
425The earth’s magnetic field at a certain place has a horizontal component of ( 0.3 G ) and total strength ( 0.5 G . ) Find
angle of dip in ( tan ^{-1} )
A ( cdot delta=tan ^{-1} frac{4}{3} )
B. ( delta=tan ^{-1} frac{3}{4} )
c. ( delta=tan ^{-1} frac{5}{3} )
D. ( delta=tan ^{-1} frac{3}{5} )
12
426The magnetic susceptibility is negative
for:
A. diamagnetic material only
B. paramagnetic material only
C . ferromagnetic material only
D. paramagnetic and ferromagnetic materials
12
427The earth behaves as a magnet with magnetic field pointing approximately from the geographic
A. North to South
B. South to North
c. East to west
D. west to East
12
428Magnetic field intensity of a shot magnet at a distance ( 1 mathrm{m} ). on axial line
is 1 Oersted. At a distance ( 2 mathrm{m} ). on the
same line the intensity in Oersted is
then :-
A . 0.75
B. 0.125
( c .0 .25 )
D. 0.5
12
429A long straight horizontal cable carries a current of ( 2.5 mathrm{A} ) in the direction ( 10^{circ} )
south of west to ( 10^{circ} ) north of east. The
magnetic meridian of the place happens to be ( 10^{circ} ) west of the geographical meridian. The earth’s magnetic field at the location is ( 0.33 mathrm{G} ) and the angle of dip is zero. Locate the line of neutral points (ignore the thickness of the cable). (At neutral points, magnetic field due to a currentcarrying cable is equal and opposite to the horizontal component of earth’s magnetic field)
A. ( 15.15 mathrm{mm} )
B . ( 30.15 mathrm{mm} )
c. ( 35.15 mathrm{mm} )
D. ( 40.15 mathrm{mm} )
12
430The angle of dip is the angle between:
A. the vertical component of earth’s magnetic field and magnetic meridian
B. the vertical component of earth’s magnetic field and geographical meridian
C . earth’s magnetic field direction and horizontal direction
D. the magnetic meridian and the geographic meridian
12
431A frog is levitated in magnetic field
produced by current in a vertical solenoid below the frog is:
A. Diamagnetic
B. Paramagnetic
c. Ferromagnetic
D. non-magnetic
12
43212. The relative permeability and permeability of a material
are er and Hp, respectively. Which of the following
values of these quantities are allowed for a diamagnetic
material?
(a) E, = 0.5, , = 0.5 (b) e, = 1.5, , = 1.5
(c) &, = 0.5, H, = 1.5 (d) €, = 1.5, H, = 0.5
(AIEEE 2008)
12
433A magnetic needle free to rotate in a vertical plane parallel to the magnetic meridian has its north tip pointing
down at ( 22^{underline{0}} ) with the horizontal. The
horizontal component of the earth’s magnetic field at the place is known to be 0.35 G. Determine the magnitude of the earth’s magnetic field at the place.
12
434A short bar magnet placed in a horizontal plane has its axis aligned along the magnetic north-south direction. Null points are found on the
axis of the magnet at ( 14 mathrm{cm} ) from the
centre of the magnet. The earth’s
magnetic field at the place is ( 0.36 mathrm{G} ) and the angle of dip is zero.What is the
total magnetic field on the normal
bisector of the magnet at the same distance as the null-point (i.e., ( 14 mathrm{cm} ) )
from the centre of the magnet? (At null points, field due to a magnet is
equal and opposite to the horizontal component of earth’s magnetic field.)
12
435A copper ring is suspended by a thread
in a vertical plane. If one end of a magnet is brought horizontally towards the ring in plane of ring as shown, the
ring will
B. not change its position
c. move away from the magnet.
D. first move towards and then move away from the magnet
12
436A South pole and North pole of each strength ‘m’ are placed at the two corners of an equilateral triangle of side ‘a’. The resultant magnetic induction field
strength at the third vertex is :
A. o (zero)
в. ( frac{2 mu_{0}}{4 pi} frac{m}{d^{2}} )
c. ( frac{mu_{0}}{4 pi} frac{m}{d^{2}} )
D. ( frac{3 mu_{0}}{4 pi} frac{m}{d^{2}} )
12
437The vertical component of the earth’s
magnetic field is zero at a place where the angle of the dip is :
A ( cdot 0^{circ} )
B . ( 45^{circ} )
( c cdot 60^{circ} )
D. ( 90^{circ} )
12
438Assertion
A current continues to flow in
superconducting coil even after switch
is off.
Reason
Superconducting coils show Meissner effect
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
43936. Which of the following relation is correct in magnetism?
(a) 1 = V2 + H2 (b) I = V+H
(c) V=1+ H2
(d) V2 = 1 + H2
12
440Identify the correctly matched pair:
A. Material – Diamagnetic Example – Gadolinium
B. Material – Soft ferromagneti Example – Alnico
C. Material – Hard ferromagneti Example – Copper
D. Material – Paramagnetic Example -Sodium
E. Material – Permanent magnet Example – Aluminium
12
441A long straight wire (radius ( =3.0 mathrm{mm}) )
carries a constant current distributed
uniformly over a cross section perpendicular to the axis of the wire. If
the current density is ( 100 mathrm{A} / mathrm{m}^{2} ). The magnitudes of the magnetic field at (a) 2.0mm from the axis of the wire and 4.0
mm from the axis of the wire is
A. ( 1.4 e-7 T )
B . ( 4 pi times 10^{-8} mathrm{T}, frac{pi}{2} times 10^{-8} mathrm{T} )
C ( cdot 4 pi times 10^{-8} mathrm{T}, frac{9 pi}{2} times 10^{-8} mathrm{T} )
D・ ( pi 10^{-4} mathrm{T}, frac{9 pi}{2} times 10^{-8} mathrm{T} )
12
442A paramagnetic liquid is taken in a Utube and arranged so that one of its limbs is kept between pole pieces of the magnet. The liquid level in the limb is
A. goes down
B. rises up
c. remains same
D. first goes down and then rise
12
443( chi_{1} ) and ( chi_{2} ) are susceptibilities of ( a )
diamagnetic substance at
temperatures ( T_{1} K ) and ( T_{2} K )
respectively, then,
A ( cdot chi_{1} T_{1}=chi_{2} T_{2} )
B . ( x_{1}=x_{2} )
c. ( chi_{1} sqrt{T_{1}}=chi_{2} sqrt{T_{2}} )
D. ( chi_{1} T_{2}=chi_{2} T_{1} )
12
444Column II gives approximate values of
magnetic field due to source given
in column I
12
445The substance used for preparing electro
magnets is :
A. soft iron
B. steel
c. nickel
D. copper
12
446Which of the following does earth’s magnetic field deflect coming from outersphere?
A. Gas atoms
B. Radioactive isotopes
c. charged particles
D. Ozone molecules
12
447A uniform magnetic field parallel to the
plane of paper, existed in space initially directed from left to right. When a bar of soft iron is placed in the field parallel to
it, the lines of force passing through it will be represented by figure.
( mathbf{A} )
B.
( c )
D.
12
448The force between two magnetic poles is ( F ) when they are separated by certain distance. If the distance between the two
poles is doubled and strength of each pole is tripled. The percentage change in the force between the two poles is :
A. ( 125 % )
B. ( 100 % )
c. ( 50 % )
D. ( 25 % )
12
449A magnetic needle suspended horizontally by an unspun silk fibre oscillates in the horizontal plane,
because of the restoring force originating mainly from
A. the torsion of the silk fibre
B. the horizontal component of earth’s magnetic field
c. the force of gravity
D. all of the above
12
4504. The magnetic lines of force inside a bar magnet
(a) are from the south pole to the north pole of the magnet
(b) are from the north pole to the south pole of the magnet
(c) do not exist
(d) depend upon the area of cross-section of the bar
magnet
(AIEEE 2003)
12
451Domain formation is the necessary
feature of
A. ferro magnetism
B. paramagnetism
c. diamagnetism
D. electro magnetism
12
452Which of the following property shows the property of ferromagnetic
substances?
A. The ferromagnetic property depends on temperature
B. The ferromagnetic property does not depend on temperature.
c. At high enough temperature ferromagnet becomes a diamagnet
D. At low temperature ferromagnet becomes a paramagnet
12
453A superconductor has ( T_{c}(0)=100 K )
When a magnetic field of 7.5 T is
applied, its ( T_{c} ) decreases to 75 K. For this
material one can definitely say that
when
A ( cdot B=5 T, T_{c}(B)=80 K )
В. ( B=5 T, 75 K<T_{c}(B)<100 K )
C . ( B=10 T, 75 K<T_{c}(B)<100 K )
D. ( B=10 T, T_{c}=70 K )
12
454The north poles of pole strengths, ( boldsymbol{m}, boldsymbol{9} boldsymbol{m} )
are kept apart by certain distance ‘ ( boldsymbol{d} ) Find distance of null point from larger
pole
A ( .2 d / 4 )
в. ( 2 d / 3 )
c. ( 5 d / )
D. ( 3 d / 2 )
12
455Compare paramagnetism and ferro magnetism. Give examples of each.12
456The ( chi-left(frac{1}{T}right) ) graph for an alloy of
paramagnetic nature is shown in figure
The curie constant is, then
( A cdot 57 K )
B . ( 2.8 times 10^{-3} K )
c. ( 570 K )
D. ( 17.5 times 10^{-3} K )
12
457A thin straight vertical conductor has
10amp current flows vertically upwards. It is present at a place where ( B_{H}=4 times 10^{-6} T . ) At which point
magnetic feild will be maximum
A. ( 0.5 m ) on south of conductor
B. ( 0.5 m ) on west of conductor
( mathrm{c} .0 .5 mathrm{m} ) on east of conductor
D. ( 0.5 m ) on north-east of conductor
12
458Two short bar magnets with magnetic moments ( 8 A m^{2} ) and ( 27 A m^{2} ) are placed
( 35 mathrm{cm} ) apart along their common axial
line with their like poles facing each
other. The neutral point is :
A. in midway between them
B. ( 21 mathrm{cm} ) from weaker magnet
c. ( 14 mathrm{cm} ) from weaker magnet
D. ( 27 mathrm{cm} ) from weaker magnet
12
459The distance between the poles of a horse shoe magnet is ( 0.1 mathrm{m} ) and its pole strength is ( 0.01 mathrm{A} ) -m. The induction of magnetic field at a point mid way between the poles will be :
A. zero
В. ( 2 times 10^{-5} T )
C ( .4 times 10^{-6} T )
D. ( 8 times 10^{-7} T )
12
46073. The magnet of vibration magnetometer is heated so as to
reduce its magnetic moment by 36%. By doing this the
periodic time of the magnetometer will
(a) increases by 36% (b) increases by 25%
(c) decreases by 25% (d) decreases by 64%
12
461Are the magnetic field lines closed?
Explain.
12
462At a given place on the earth’s surface, the horizontal component of earth’s
magnetic field is ( 3 times 10^{-6} T ) and
resultant magnetic field is ( 6 times 10^{-6} T )
Angle of dip at this place is :
A . ( 30^{circ} )
B . ( 40^{circ} )
( c cdot 50^{circ} )
D. ( 60^{circ} )
12
463When magnetic field at ( mathrm{P} ) and ( mathrm{Q} ) is same then OP/OQ is:
A ( cdot frac{1}{3} )
B. ( frac{1}{frac{1}{3}} )
( c cdot 2 sqrt{2} )
D. ( frac{3}{2} )
12
464Column I shows different positions in
which one pole of a magnet is placed near that of the other.
Column II indicates the resulting action between them for each situation. Fill in
the blanks.
Column I ||
( N-N )
Attraction
( s-1 )
Repulsion
12
465Which of the following group is diamagnetic?
A. Copper, hydrogen, silver
B. Copper, hydrogen, argon
c. Hydrogen, oxygen, argon
D. Copper, silver, oxygen
12
466A magnet has coercivity of ( 3 times 10^{3} )
( A m^{-1} . ) It is kept in a ( 10 mathrm{cm} ) long solenoid
with a total of 50 turns. How much
current has to be passed through the solenoid to demagnetize it?
12
467At the centre of which of the following four circular rings is the magnetic field strongest, for equal magnitude of
current?
A . 3
B.
( c cdot 4 )
( D )
12
468Define magnetic declination.12
469Two identical short magnets having magnetic moment M are placed perpendicular to each other centres
coinciding as shown in adjacent figure. The magnitude of the magnetic field at
a point ( P ) at angle distance ‘d’ on the bisector of right angle will be :
A. ( frac{sqrt{2} mu_{0} M}{4 pi d^{3}} )
B. ( frac{2 sqrt{2} mu_{0} M}{4 pi d^{3}} )
c. ( frac{2 mu_{0} M}{4 pi d^{3}} )
D. ( frac{sqrt{3} mu_{0} M}{4 pi d^{3}} )
12
470The horizontal and vertical components
of earth’s magnetic field at a place are ( 0.3 G ) and ( 0.52 G . ) The earth’s magnetic
field and the angle of dip are
A ( cdot 0.3 mathrm{G} ) and ( rho=30^{circ} )
B. 0.4G and ( rho=40^{circ} )
c. ( 0.5 mathrm{G} ) and ( rho=50^{circ} )
D. ( 0.6 mathrm{G} ) and ( rho=60^{circ} )
12
471The period of osillation of a freely suspended bar magnet is 4 second. If it
is cut into two equal parts in length, then the time period of each part will be
A. 4 sec
B. 2sec
c. ( 0.5 s e c )
D. 0.25 sec
12
47210. Needles Ni, N2, and Nz are made of ferromagnetic,
paramagnetic, and diamagnetic substances, respectively.
A magnet when brought close to them will
(a) attract N, strongly, but repel N2 and Nz weakly
(b) attracts all three to them
(c) attract N, strongly, N, weakly and repel N, weakly
(d) attract N, and N2 strongly but repel N3
(AIEEE 2006)
12
473Force acting between two small magnets, placed in end on position
( 0.1 m ) apart from their centres is
(Given magnetic moment of each
magnet is ( left.5 A m^{2}right) )
A . ( 0.6 N )
B. ( 0.8 N )
c. ( 0.15 N )
D. ( 0.2 N )
12
47417. A compass needle of magnetic moment 60 Am² pointing
geographical north at a place where the horizontal
component of earth field is 40 u Wb m-experiences a
torque of 1.2 x 10-Nm.
(a) 15°
(b) 30°
(c) 45°
(d) 60°
12
475Calculate the magnetic field generated
by n segment of an right triangle.
12
476Distinguish between Para, Ferro and Diamagnetism.12
477A charged particle is moved along a magnetic field line.The magnetic force on the particle is
A. opposite to its velocity
B. along its velocity
c. zero
D. perpendicular to its velocity
12
478Which of the following substances are para-magnetic? ( boldsymbol{B} boldsymbol{i}, boldsymbol{A l}, boldsymbol{C u}, boldsymbol{C a}, boldsymbol{P b}, boldsymbol{N i} )12
479An electron makes ( 3 times 10^{5} ) revolutions
per second in a circle of radius 0.5
angstrom. Find the magnetic field ( B ) at
the centre of the circle.
12
480The dip at the poles is
( mathbf{A} cdot 80 )
B. 60
c. 90
D. 0
12
481Answer the following questions:
(a) Explain qualitatively on the basis of domain picture the irreversibility in the magnetisation curve of a ferromagnet.
(b) The hysteresis loop of a soft iron piece has a much smaller area than
that of a carbon steel piece. If the material is to go through repeated cycles of magnetisation, which piece will dissipate greater heat energy?
(c) ‘A system displaying a hysteresis loop such as a ferromagnet, is a device for storing memory? Explain the meaning of this statement.
(d) What kind of ferromagnetic material is used for coating magnetic tapes in a cassette player, or for building ‘memory stores’ in a modern computer?
(e) A certain region of space is to be shielded from magnetic fields. Suggest a method.
12
482Magnetic permeability of paramagnetic substances is?
( mathbf{A} cdot mathbf{0} )
B ( .>1 )
( c cdot<1 )
D.
12
483If the earth does not rotate on its axis,
the change in the weight of a body at the equator would be about (Take radius of earth-6400 ( mathrm{km} ) )
A. 0.003%v larger
B. 0.3% longer
c. ( 0.3 % ) smaller
D. 0.003% smaller
12
484Assume the dipole model for earth’s magnetic field B which is given by thevertical component of magnetic field, ( B_{V}=frac{mu_{o}}{4 pi} frac{2 m cos theta}{r^{3}} ) and the
horizontal component of magnetic field ( B_{H}=frac{mu_{o}}{4 pi} frac{m sin theta}{r^{3}}, ) where ( theta=90^{circ}- )
latitude as measured from magnetic
equator, then the loci of point for which
dip angle is ( pm mathbf{4 5}^{circ} )
( mathbf{A} cdot tan ^{-1}(3) )
( mathbf{B} cdot tan ^{-1}(2) )
( mathbf{c} cdot tan ^{-1}(0.5) )
( mathbf{D} cdot tan ^{-1}(1) )
12
485A telephone cable at a place has four long straight horizontal wires carrying a current of ( 1.0 mathrm{A} ) in the same direction
east to west. The earth’s magnetic field at the place is ( 0.39 mathrm{G}, ) and the angle of
dip is ( 35^{circ} ).The magnetic declination is
nearly zero. What are the resultant magnetic fields at points ( 4.0 mathrm{cm} ) below the cable?
12
486is present around the
magnet.
12
48719. The force between two short bar magnets with magnetic
moments M and M2 whose centres are r metre apart is
0.8 N when their axes are in the same line. If the separation
is increased to 2r, then force between them is reduced to
(a) 4.0 N
(b) 2.0 N
(c) 1.0 N
(d) 0.5 N
12
488A permanent magnet
A. attracts all substances
B. attracts only ferromagnetic substances
C . attracts magnetic substances and repels all others
D. attracts some substances and repels others
12
489A very long magnet is placed vertically with one pole on the table. A neutral
point was found at ( 20 mathrm{cm} ) from the pole. What is the pole strength if the vertical
component of earth’s field is ( 0.4 times )
( 10^{-4} W b m^{-2} ? )
( mathbf{A} cdot 16 A-m )
в. ( 8 A-m )
( mathrm{c} cdot 4 A-m )
D. None of these
12
490The vertical component of earth’s magnetic field is zero at
A. magnetic equator
B. magnetic poles
c. geographical poles
D. everywhere
12
491The magnetic lines of forces due to the horizontal component of Earth’s magnetic field will be
A . circular
B. elliptical
c. curved
D. horizontal and parallel
12
492At a place on the surface of earth vertical component of earths field is two times that of horizontal component.
Then the latitude angle at the place is
( mathbf{A} cdot tan ^{-1}(2) )
B cdot ( tan ^{-1}(1 / 2) )
( c cdot 45^{circ} )
D. ( 0^{circ} )
12
493allo1
26. In a vibration magnetometer, the time period of a bar
magnet oscillating in horizontal component of earth’s
magnetic field is 2 s. When a magnet is brought near and
parallel to it, the time period reduces to 1 s. The ratio
H/F of the horizontal component H, and the field F due
to magnet will be
(a) 3
(b) 1/3
(c) 13
(d) 1/3
12
494Two points ( A ) and ( B ) are situated at
distance ( x ) and ( 2 x ) respectively from the
nearer pole of a magnet 2cm long. The
ratio of magnetic field at ( A ) and ( B ) is?
A. 4: 1 exactly
B. 4 : 1 approximately
c. 8: 1 exactly
D. 8: 1 approximately
12
495An electron enters a chamber in which a
uniform magnetic field is present as
shown.
An electric feild of appropriate magnitude is also applied so that the electron travels undeviated without any
change in its speed through the
chamber. We are ignoring gravity. Then,
the direction of the electric field is
A. Opposite to the direction of the magnetic field.
B. Opposite to the direction of the electron’s motion.
C. Normal to the plane of the paper and coming out of the plane of the paper.
D. Normal to the plane of the paper and into the plane of the paper.
12
496What is the unit of ratio ( frac{E}{H} ? )12
497A bar magnet has coercivity ( 4 times ) ( 10^{3} A m^{-1} . ) It is placed in a solenoid
having 40 turns per ( mathrm{cm} ) and is ( 1.2 mathrm{m} ) long. The current carried by the solenoid to demagnetize the bar magnet is :
( A cdot 6 A )
в. ( 8 A )
c. ( 5.78 A )
D. none of these
12
498Two magnetic poles of pole strengths ( 324 m A-m ) and ( 400 m A-m ) are kept at
a distance of ( 10 mathrm{cm} ) in air. The null point will be at a distance of
on the line joining the two poles, from the weak pole if they are like poles:
A. 4.73
B. 5
( c .6 .2 )
D. 5.27
12
499Which of the following is responsible for the earth’s magnetic field?
A. Convective currents in earth’s core
B. Diversive current in earth’s core
c. Rotationa motion of earth.
D. Translational motion of earth
12
500A long straight horizontal cable carries a current of ( 2.5 mathrm{A} ) in the direction ( 10^{0} )
south of west to ( 10^{0} ) north of east. The
magnetic meridian of the place
happens to be ( 10^{0} ) west of the
geographic meridian. The earth’s magnetic field at the location is ( 0.33 mathrm{G} ) and the angle of dip is zero. Locate the line of neutral points (ignore the thickness of the cable). (At neutral points, magnetic field due to a current carrying cable is equal and opposite to the horizontal component of earth’s magnetic field.)
A. ( 15.15 mathrm{mm} )
B. ( 30.15 mathrm{mm} )
c. ( 35.15 mathrm{mm} )
D. ( 40.15 mathrm{mm} )
12
501Whm ( ^{-2} ) is equal to
( A cdot 10^{4} G )
B . ( 10^{2} ) G
( c cdot 10^{-2} mathrm{G} )
D. ( 10^{-4} mathrm{G} )
12
50223. If the total magnetic field due to earth is 28 A/m , then the
total magnetic induction due to earth is
(a) 28 T
(b) 280 T
(c) 0.352 gauss
(d) 0.352 T
12
503The magnetic field intensity due to a bar
magnet is ( 100 mathrm{Am}^{-1} ). The magnetic
induction field strength due to it is:
A ( cdot frac{4 pi}{10^{7}} T )
B. ( frac{4 pi}{10^{5} T} )
( ^{mathbf{C}} cdot frac{10^{3}}{4 pi} T )
D. ( frac{10^{5}}{4 pi} T )
12
504If a magnet is suspended at an angle
( 30^{circ} ) to the magnetic meridian, the dip
needle makes angle of ( 45^{circ} ) with the horizontal. The real dip is :
A ( cdot tan ^{-1}(sqrt{3} / 2) )
B. ( tan ^{-1}(sqrt{3}) )
( mathbf{c} cdot tan ^{-1}(sqrt{3} / sqrt{2}) )
D. ( tan ^{-1}(2 / sqrt{3}) )
12
505The dependence of the critical
temperature for superconductivity
upon
A. isotopic mass
B. isotonic mass
c. isobaric mass
D. Both A and B
12
506Tangent law is applicable only when
A. applied field is parallel to the earth’s horizontal component
B. applied field is antiparallel to the earth’s horizontal component
C . applied field is perpendicular the earth’s horizontal component in horizontal plane
D. applied field is inclined to the earth’s horizontal component
12
507Write three difference between
diamagnetic and paramagnetic
substances.
12
508Needles ( N_{1}, N_{2} ) and ( N_{3} ) are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A
magnet when brought close to them will
A. attract all three of them.
B. attract ( mathrm{N}_{1} ) and ( mathrm{N}_{2} ) strongly but repel ( mathrm{N}_{3} )
C. attract ( mathrm{N}_{1} ) strongly, ( mathrm{N}_{2} ) weakly and repel ( mathrm{N}_{3} ) weakly
D. attract ( mathrm{N}_{1} ) strongly, but repel ( mathrm{N}_{2} ) and ( mathrm{N}_{3} ) weakly
12
509In a plane perpendicular to the magnetic meridian the dip needle will
remain :
A. Vertical
B. Horizontal
C. At an angle of ( 45^{circ} ) from horizontal
D. At an angle of ( 60^{circ} ) from vertical
12
510The needle of the dip circle of a place
stay at ( 30^{0} . ) The dip circle is inclined at
an angle towards ( 30^{0} ) with the magnetic
meridian. The true dip at the place is:
A ( cdot tan ^{-1} sqrt{3} )
B. ( tan ^{-1} frac{sqrt{3}}{2} )
c. ( tan ^{-1} frac{1}{2} )
D. ( tan ^{-1} frac{3}{2} )
12
51131. A magnet needle makes 4 vibrations per second at a place
where H = 3.5 x 10- T. What is the value of H at place,
where the same needle makes 3 vibrations per second?
(a) 1.98 x 10-T (b) 3.5 x 10-5T
(c) 4.0 x 10-5T (d) 3.96 x 10-5T
12
512Write on expression for vector from of magnetic force on a moving charge.12
513The angles of dip at the poles and the equator respectively are.
A . ( 30^{circ}, 60^{circ} )
B . ( 0^{circ}, 90^{circ} )
c. ( 45^{circ}, 90^{circ} )
D. ( 90^{circ}, 0^{circ} )
12
514Define magnetic lines of force and state its two properties.12
515The plane of a dip circle is set in the geographical meridian and the apparent dip is ( theta_{1} ). If it is set in a vertical plane perpendicular to the geographical meridian, then the
apparent dip becomes ( theta_{2} ). The angle of declination ( alpha ) at the given place is given by :
A. ( tan alpha=sqrt{left(tan theta_{1} tan theta_{2}right)} )
B. ( tan alpha=frac{tan theta_{1}}{tan theta_{2}} )
( c cdot tan alpha=tan theta_{1}+tan theta_{2} )
D. ( tan alpha=frac{tan theta_{2}}{tan theta_{1}} )
12
516Curie temperature is defined as the
temperature above which.
A. A paramagnetic material becomes ferromagnetic
B. A ferromagnetic material becomes paramagnetic
C. A ferromagnetic material becomes diamagnetic
D. A diamagnetic material becomes ferromagnetic
12
517The magnetic force required to demagnetise the material is
A. retentivity
B. coercivity
c. energy loss
D. hysterisis
12
518If ( chi ) stands for the magnetic
susceptibility of a substance, ( mu ) for its
magnetic permeability and ( mu_{0} ) for the permeability of free space, then This question has multiple correct options
A. For a paramagnetic substance: ( chi>0, mu>0 )
B. For a paramagnetic substance: ( quad chi>0, quad mu>mu_{0} )
c. For a diamagnetic substance: ( chi<0, mu1, mu<mu_{0} )
12
519Susceptibility is small and negative for
A. para magnetio
B. diamagnetic
C. ferro magnetic
D. electromagnetic
12
520Susceptibility is positive and large for a
A. paramagnetic substance
B. ferromagntic substance
c. diamagnetic substance
D. non magnetic substance
12
521Problems Based on Mixeu Concepts
55. Ata certain place, the angle of dip is 50° and the horizontal
component of earth’s field is 0.15 T. A beam of protons is
moving vertically upwards with a speed of 3 x 10 ms.
The force on proton is [cos 50º = 0.6, sin 50º = 0.8]
(a) 4.39 x 10-15 N (b) 5.88 x 10-15 N.
(c) 8.60 x 10-15 N (d) 7.20 x 10-15 N
The manatia field intoncitu Lot the montofle
12
522Assertion
The product of magnetic susceptibility and absolute temperature for a paramagnetic substance is constant
Reason

Susceptibility is positive but very small
for paramagnetic substance.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

12
523Field lines are shown close together
where the
A. magnetic field is far apart
B. magnetic fields is zero
c. magnetic fields is greater
D. all
12
524A magnetic needle makes an angle of 45 with the thread from which it is
suspended then
A. Dip at that place is 45
B. Inclination at that place is 45
c. Declination angle at that place is 45
D. Both (1) and (2)
12
525At a place on the surface of earth vertical component of earth’s field is two times that of horizontal component.
Then the latitude angle at that place is
( mathbf{A} cdot tan ^{-1}(2) )
B cdot ( tan ^{-1}(1 / 2) )
( c cdot 45^{circ} )
D. ( 0^{circ} )
12
526Ferromagnetic materials have their
properties due to
A. vacant inner subshells
B. partially filled inner subshells
C. filled inner subshells
D. completely filled outer shells
12
527The curie weiss law is obeyed by iron
A. at all temperatures
B. above the curie temperature
C . below the curie temperature
D. at the curie temperature
12
528The angle of dip at a place where horizontal and vertical components of Earth’s magnetic field are equal is
A ( .45^{circ} )
B. ( 30^{circ} )
( c cdot 0^{circ} )
D. ( 60^{circ} )
E ( .90^{circ} )
12
529You are provided with two similar bars. One is magnet and the other is a soft iron. How will you distinguish between
them without the use of any other magnet or bar?
12
530Ferromagnetic ore properties are due to
A. filled inner sub-shells
B. vacant inner sub-shells
C . partially filled inner sub-shells
D. all the sub-shells equally filled
12
531Two magnets are kept one above the other and made to oscillate in
horizontal plane. The period combination is 6 second. When one of
the magnets is reversed pole to pole, the period of oscillations of combination is
3 second. Compare the magnetic pole moments of the two magnets.
12
532Q Type your question
substance is best represented by figure
( A )
B.
( c )
( D )
12
533The total number of magnetic lines of
force originating or terminating on a pole of strength ( mathrm{m} ) is :
A. ( frac{mu_{o} m}{4 pi} )
в. ( frac{m}{mu_{o}} )
( c cdot m^{2} )
D. ( mu_{o} m )
12
534A cylindrical rod magnet has a length of ( 5.0 mathrm{cm} ) and a diameter of ( 1.0 mathrm{cm} . ) It has a
uniform magnetization of ( 5.3^{*} 10^{3} mathrm{A} / mathrm{m} ) What is its magnetic dipole moment?
A . 20.8 ( m J T^{-1} )
B . ( 10.8 m J T^{-1} )
( mathbf{c} cdot 5.8 m J T^{-1} )
D. 30.8mJT”
12
535(a) State Gauss’ law for magnetism.
(b) How this differs from Gauss’ law for
electrostatics?
(c) Why is the difference in the two cases?
12
536A magnet of dipole moment ( 2 A m^{2} ) is
deflected through ( 30^{circ} ) from magnetic meridian. The required deflecting
torque is ( left(B_{H}=0.4 times 10^{-4} Tright) )
A ( cdot 0.4 times 10^{-4} mathrm{Nm} )
B. ( 0.4 mathrm{Nm} )
c. ( 0.2 times 10^{-4} N m )
D. None of these
12
537( t )12
538Find the interaction force of two coils
with magnetic moments ( boldsymbol{p}_{1 m}=mathbf{4 . 0} boldsymbol{m} boldsymbol{A} )
( -m^{2} ) and ( p_{2 m}=6.0 m A-m^{2} ) and
collinear axes if the separation between the coils is equal to ( l=20 mathrm{cm} ) which
exceeds considerably their linear dimensions.
A . 9
B. 5
c. 8
D. 10
12
539Two small bar magnets are placed in a line at certain distance ( d ) part. If the
length of each magnet is negligible compared to ( d ), the force between them will be inversely proportional to:
( mathbf{A} cdot d^{2} )
B. ( d )
( c cdot d^{3} )
D. ( d^{4} )
12
540Which part has maximum attraction in a magnet?
A. In the centre
B. on the sides
c. on the poles
D. on the surface
12
541Define transition temperature.12
54240. If a magnetis suspended at an angle 30 to the magnet
meridian, it makes an angle of 45′ with the horizontal
The real dip is
(a) tan(13/2) (b) tan (13)
(e) tan(3/2) (d) tan (2/13)
12
54316. Hysteresis loops for two magnetic materials A and B are
given below:
→H –
H
(A)
(B)
These materials are used to make magnets for electric
generators, transformer core and electromagnet core.
Then it is proper to use
(a) A for electric generators and transformers
(b) A for electromagnets and B for electric generators
(c) A for transformers and B for electric generators
(d) B for electromagnets and transformers
(JEE Main 2016)
12
544Assertion: The properties of paramagnetic and ferromagnetic substances are not affected by heating.
Reason: As temperature rises, the alignment of molecular magnets gradually decreases
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not correct explanation of A
c. A is true, but R is false
D. A is false, but R is true
12
545Assertion
Ferro-magnetic substances become paramegnetic above Curie temp
Reason

Domains are destroyed at high
temperature.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

12
546What is hysteresis? Define the terms ‘coercivity’ and ‘retentivity’ of a ferromagnetic material.12
54729. Two bar magnets of the same mass, same length and
breadth but having magnetic moments M and 2M are
joined together pole for pole and suspended by a string.
The time period of assembly in a magnetic field of strength
Hy is 3 seconds. If now the polarity of one of the magnets
is reversed and the combination is again made to oscillate
in the same field, the time of oscillation is
(a) V3
(e) 3
(d) 6
(b) 3V3
12
548At Curie temperature, in ferromagnetic
materials
A. the atomic dipoles get aligned
B. the atomic dipoles remains stationary
C. the atomic dipoles lose alignment
D. magnetism is zero
12
549Assertion: Paramagnetic substances get weakly attracted to a magnet. Reason : They have tendency to move from a region of strong magnetic field to weak magnetic field
A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true and reason is not the correct explanation of assertion
c. If assertion is true but reason is false
D. If both assertion and reason are false
12
550toppr
-०६॥
Q Type your question_
placed the ends ( (X text { and } Y) ) of each
object, near the north pole of the bar magnet and recorded his observations
in the table below.
End Y brought End X
Object brought near near
to N pole to N pole
N pole repelled ( quad ) N pole attracted ”
N pole
attracted ( quad ) N pole repelled
( begin{array}{ll}text { N pole } & text { N pole remains } \ text { remains } & text { stationary } \ text { stationary } & end{array} )
Which of the object(s) is/are the magnet?
Bar magnet Object
A. P only
( c )
D. P and R only
12
55165. A magnetic dipole is under the effect of two magn
fields inclined at 75° to each other. One of the fields
a magnitude of 1.5 x 10°-T. The magnets come to stable
position at an angle of 30° with the direction of the al
field. The magnitude of other field is
(a) 1.5 x10-21 (b) x10-2T
25×10
(c) 1.5x 12 x10-21
(d) 1.5×10-2T
12
552A magnetic field exists in the region surrounding a magnet, in which the force of the magnet can be detected. Is the given statement true or false?12
553The lines of force of a bar magnet are:
A. Parallel and straight
B. Concentric circles
c. Curved lines
D. Curved closed loops
12
554A compass needle whose magnetic moment is ( 60 A m^{2} ) pointing geographical north at a certain place
where the horizontal component of earth’s magnetic field is ( 40 times 10^{-6} mathrm{Wb} )
( m^{-2} ) experiences a torque of ( 1.2 times 10^{-3} )
N m. The declination of the place is?
A ( cdot 20^{circ} )
B . ( 45^{circ} )
( c cdot 60^{circ} )
D. ( 30^{circ} )
12
555Angle of dip ( delta ) and latitude ( lambda ), on earth’s
surface are related as
( mathbf{A} cdot tan delta=2 tan lambda )
B. ( tan delta=cot lambda )
( mathbf{C} cdot tan delta=frac{tan lambda}{2} )
D. ( tan delta=tan lambda )
12
556Few iron nails and screws got mixed
with wood shavings while a carpenter was working with them. How can you help him in getting the nails and screws back from the scrap without wasting his time by searching with his hands?
12
557A thin rectangular magnet suspended freely has a period
of oscillation equal to T. Now it is broken into two equal
halves (each having half of the original length) and one
piece is made to oscillate freely in the same field. If its
period of oscillation is T’, the ratio T/T is
1
(b)
212
(d) 2
(AIEEE 2003)
12
558Above Curie temperature, ferromagnetic substances become
A. diamagnetic
B. paramagnetic
c. ferrimagnetic
D. none of these
12
559The corecivity of a small magnet where the ferromagnet gets demagnetized is
( 3 times 10^{3} A m^{-1} . ) The current required to
be passed in a solenoid of length ( 10 mathrm{cm} )
and number of turns ( 100, ) so that the magnet gets demagnetized when inside the solenoid is:
( A cdot 3 A )
в. ( 6 A )
( c .30 m A )
D. ( 60 m A )
12
560The correct value of dip angle at a place
is ( 45^{circ} . ) If the dip circle is rotated by ( 45^{circ} ) out of the meridian, then the tangent of the angle of apparent dip at the place is
A . 1
B. ( 1 / 2 )
c. ( 1 / sqrt{2} )
D. ( sqrt{2} )
12
561At a given place on earth’s surface the horizontal component of earths magnetic field is ( 2 times 10^{-5} mathrm{T} ) and
resultant magnetic field is ( 4 times 10^{-5} mathrm{T} )
The angle of dip at this place is?
A . ( 30^{circ} )
B. ( 60^{circ} )
( c cdot 90^{circ} )
D. ( 45^{circ} )
12
562Needles ( N_{1}, N_{2}, N_{3} ) are made of a
ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A
magnet when brought close to them will:
A. attract ( N_{1} ) and ( N_{2} ) strongly but repel ( N_{3} )
B. attract ( N_{1} ) strongly, ( N_{2} ) weakly and repel ( N_{3} ) weakly
C. attract ( N_{1} ) strongly, but repel ( N_{2} ) and ( N_{3} ) weakly
D. attract all three of them
12
563Assertion
Magnetic field interacts with a moving charge and not with a stationary charge.
Reason

A moving charge produces a magnetic field.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Assertion is incorrect but Reason is correct

12
564Permanent magnets are made from
A. diamagnetic substances
B. paramagnetic substance
C. ferromagnetic substances
D. wood
12
565Needles ( N_{1}, N_{2} ) and ( N_{3} ) are made of a ferromagnetic, a paramagnetic and a diamagnetic substance respectively. A
magnet when brought close to them will?
A. Attract all three of them
B. Attract ( N_{1} ) strongly, ( N_{2} ) weakly and repel ( N_{3} ) weakly
C. Attract ( N_{1} ) strongly but repel ( N_{2} ) and ( N_{3} ) weakly
D. Attract ( N_{1} ) and ( N_{2} ) strongly but repel ( N_{3} )
12
566State and explain Curie’s law.12
567Among which the magnetic susceptibility does not depend on the temperature?
A. Dia-magnetism
B. Para-magnetism
c. Ferro-magnetism
D. Ferrite
12
568At what distance on the axis, from the
centre of a circular current carrying coil of radius ( r, ) the magnetic field becomes 1/8th of the magnetic field at centre?
A ( cdot sqrt{2} r )
B ( cdot 2^{3 / 2} )
( c cdot r sqrt{3} )
D. ( 3 sqrt{2} r )
12
569Assertion
Diamagnetism is universal, it is
present in all materials.
Reason
Field due to induced magnetic moment is opposite to the magnetising field.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
570The force between two magnetic poles
reduces to ( a N, ) if distance between
them is increased to ( n ) times and it
increases to ( b N ) if the distance between
them is ( 1 / n^{t h} ) the original value. Then
( a: b ) is :
( A cdot 1 cdot n^{2} )
B ( cdot n^{2}: )
( c cdot n^{4} cdot 1 )
( D cdot 1: n^{4} )
12
571If the bar magnet is turned around by
( 180^{circ}, ) where will the new null points be located?
12
572Out of the two magnetic materials, ‘A’ has relative permeability slightly greater than unity while ‘B’ has less than unity. Identify the nature of the materials ‘A’ and ‘B’. Will their
susceptibilities be positive or negative?
12
573(c) 7.54 Am
69. An iron rod of volume 10m and relative permeability
1000 is placed inside a long solenoid wound with
5 turns/cm. If a current of 0.5 A is passed through the
solenoid, then the magnetic moment of the rod is
(a) 10 Am
(b) 15 Am
(c) 20 Am?
(d) 25 Am
not be cercivity y 103 Am-1 It is de

A
1
12
574Two circular coils each of 100 turns are
held such that one lies in the vertical
plane and the other in the horizontal plane with their centres coinciding. The radius of vertical and horizontal coils
are ( 20 mathrm{cm} ) and ( 30 mathrm{cm} ) respectively. If the magnetic field at their common centre is zero, find current in each coil
Horizontal component of earth’s magnetic field is 27.8 Aim and angle of
dip at this place is ( 30^{circ} )
12
575At a place of Earth, the vertical component of Earth’s magnetic field is ( sqrt{3} ) times its horizontal component. The angle of dip at this place is
A .60
B. 30
c. 45
D. 0
12
576The magnets shown here will
A. Attract each other
B. Repel each other
c. Pull each other
D. cannot say
12
57727. The magnetic needle of an oscillation magnetometer
makes 0 oscillations per minute under the action of earth’s
magnetic field only. When a bar magnet is placed at some
distance along the axis of the needle, it makes 14 oscillations
per minute. If the bar magnet be turned so that its poles
interchange the positions, the new frequency of the needle is
(a) 2 oscillations per minute
(b) 12 oscillations per minute
(c) 20 oscillations per minute
(d) 69.7 oscillations per minute
12
57861. A bar of mass M is suspended by two wires. Assume that
a uniform magnetic field B is directed into the page. When
the current through the bar is 1, then the tension in each
supporting wire is
(a) Mg
(b) 2BIL
Mg- BIL
(c) Mg – BIL
12
579When two magnetic poles having same
pole strength are separated by a distance of ( 20 mathrm{cm}, ) a force of ( 5 mathrm{N} ) acts
between them. If the distance is halved, the force becomes
A . 20 N
B. 10 N
( c .15 mathrm{N} )
D. 25 N
12
580At a place the value of ( B_{H} ) and ( B_{V} ) are ( 0.4 times 10^{-4} ) and ( 0.3 times 10^{-4} ) respectively.
The resultant earths magnetic field is :
A ( .0 .5 times 10^{-4} T )
в. ( 10^{-4} T )
c. ( 2 times 10^{-4} T )
D. ( 5 times 10^{-4} T )
12
581A magnetic needle is kept in a
nonuniform magnetic field. It
A. may experience a force but certainly not a torque
B. may experience a torque but certainly not a force
C. may experience both a torque as well as force
D. will certainly experience neither a force not a torque
12
582A dip circle shows an apparent dip of ( 60^{0} ) at a place where the true dip is ( 45^{0} )
If the dip circle is rotated by ( 90^{0}, ) what will be the apparent dip?
( ^{mathbf{A}} cdot cos ^{-1} sqrt{frac{2}{3}} )
B. ( tan ^{-1} sqrt{frac{2}{3}} )
( c cdot sin ^{-1} sqrt{frac{2}{3}} )
D. ( cot ^{-1} sqrt{frac{2}{3}} )
12
583For diamagnetic materials, magnetic susceptibility is
A. Small and negative
B. Small and positive
c. Large and negative
D. Large and positive
12
584A South pole and North pole of each strength ‘m’ are placed at the two corners of an equilateral triangle of side ‘a’. The resultant magnetic induction field
strength at the third vertex is :
A. o (zero)
в. ( frac{2 mu_{0}}{4 pi} frac{m}{d^{2}} )
c. ( frac{mu_{0}}{4 pi} frac{m}{d^{2}} )
D. ( frac{3 mu_{0}}{4 pi} frac{m}{d^{2}} )
12
585Observe the given figure and identify
the correct statements.
(i) Poles 1,3 and 5 are unlike poles
(ii) Poles 2,4 and 6 are like poles
(iii) Pole 1 will attract pole 3 and 5
(iv) Pole 4 will be attracted by pole 1
begin{tabular}{|l|l|l|}
hline 1 & 2 & 3 & 4 & 5 \
hline Magnet & Magnet & Magnet
end{tabular}
A. Only (i) and (iii)
B. Only (ii) and (iv)
c. Only (i) and (ii)
D. Only (iii) and (iv)
12
586Assertion (A): To protect any
instrument from external magnetic field, it is put inside an iron box Reason (R) : Iron is a ferromagnetic
substance
A. Both A and R are true and R is the correct explanation of A
B. Both A and R are true and R is not correct explanation of
c. A is true, but R is false
D. A is false, but R is true
12
587A student uses a magnetic compass to
perform a laboratory experiment in the Northern Hemisphere. She then carries the same magnetic compass with her to the Southern Hemisphere, taking care not to damage the compass in any way. When she reaches her destination at the equivalent latitude and longitude in the Southern Hemisphere, she prepares to perform the same laboratory experiment. The student looks at the compass before performing the experiment to see if the compass needle has changed. How has the compass changed?
A. The compass needle points ( 90^{circ} ) to the left of the expected direction
B. The compass needle points ( 90^{circ} ) to the right of the expected direction
c. The compass needle slowly rotates in a counter clockwise direction
D. The compass needle slowly rotates in a clockwis tion
as been no he co
12
588A dip needle on a plane perpendicular to magnetic meridians will remain
A. horizontal
B. vertical
c. inclined at ( 45^{circ} ) with horizontal
D. in any direction
12
589A watch glass containing some powdered substance is placed between
the pole pieces of a magnet. Deep concavity is observed at the centre. The substance in the watch glass is
A. iron
B. chromium
c. carbon
D. woodd
12
590To explain ferromagnetism, we use
A. orbital electron hypothesis
B. spinning electron hypothesis
C. domain theory
D. Langevin theory
12
591An aeroplane with wing span ( 50 m ) is flying horizontally with a speed of ( 360 k m / h r ) over a place where the
vertical component of the earth’s magnetic field is ( 2 times 10^{-4} W b / m^{2} . ) The
potential difference between the tips of the wings would be
A . ( 0.1 V )
в. ( 1.0 V )
( c .0 .2 V )
D. ( 0.01 V )
12
592A bar magnet is ( 10 mathrm{cm} ) long is kept with its north (N)-pole pointing north. A neutral point is formed at a distance of ( 15 mathrm{cm} ) from each pole:Given the horizontal component of earth’s field is 0.4 Gauss, the pole strength of the magnet is
( A cdot 9 A-m )
B. 6.75 A-m
c. 27 A-m
D. 1.35 A-m
12
593The vertical component of the earth’s magnetic field is:
A. zero at the magnetic pole
B. Zero at the geographic pole
c. Same everywhere
D. zero at the magnetic equator
12
594A magnetic dipole is placed in a uniform magnetic fields, B, the potential energy is minimum when dipole is
A. Parallel to B
B. Perpendicular to B
c. Inclined at an angle of 450 to ( B )
D. Anti-parallel to B
12
595When a bar magnet is broken into two pieces:
A. we will have a single pole on each piece
B. each piece will have two unlike poles
c. each piece will have two like poles
D. none of these
12
596A conducting rod of length ( 2 mathrm{m} ) is placed on a horizontal table in north-south
direction. It carries a current of 5 A from
south to north. Find the direction and
magnitude of the magnetic force acting on the rod. Given that the Earth’s
magnetic field at the place is ( 0.6 times ) ( 10^{-4} T ) and angle of dip is ( frac{pi}{6} )
12
597A material produces a magnetic field which helps the applied magnetic field, then it is
This question has multiple correct options
A. diamagnetic
B. paramagnetic
c. electro magnetic
D. ferro magnetic
12
598Earth’s magnetic field inside a closed iron box, as compared to that outside is
A. same
B. less
c. more
D. zero
12
599Magnetic lines form continuous closed loops. Why?12
600The magnetic induction due to short bar magnet on its axial line at a
distance ‘ ( d ) ‘ is ‘ ( B ) ‘. What is the magnetic
induction due to the same bar magnet
on the same line at a distance
(a) ( d / 4 ? )
(b) ( 4 d / 5 ? )
(b) ( 125 / 64 B )
в. (а) ( 64 B )
(b) ( 125 / 64 B )
c. (a) ( 32 B )
(b) ( 125 / 32 B )
D. (a) ( 64 B )
(b) ( 125 / 32 B )
12
601State the characteristics of magnetic
lines of force.
12
602Current is flowing through a conductor
and creates a magnetic field. Assume
that this is the only source of the
magnetic field. Reversing a current in a straight conductor with no change to
the magnitude(ampere value) will
cause a
A. Reduction in the magnetic field
B. Disappearance of the magnetic field
C. Reversal of the direction of the magnetic field
D. Reversal and reduction of the magnetic field
12
603The pole strength of a bar magnet is 2 Am. If the field at poles are ( 0.2 mathrm{T} ) and 0.22 T, then the force acting on the bar magnet is
consider field direction to be same
A. ( 0.4 mathrm{N} )
B. 0.04N
c. ( 0.44 mathrm{N} )
D. 0.8N
12
604A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. In which direction will it move?
A. Away from bar magnet
c. Around the bar magnet
D. Remain constant
12
605The strength of magnetic field around a
bar magnet:
A. decrease with the decrease in distance from the magnet
B. decrease with the increase in distance from the magnet
c. remain constant with increase in distance from magnet
D. becomes zero with decrease in distance from magnet
12
606Nickel shows ferromagnetic property at room temperature. If the temperature is increased beyond Curie temperature,
then it will show the
A. anti ferromagnetism
B. no magnetic property
c. diamagnetism
D. paramagnetism
12
607( mathbf{A} )
is a region around a magnet where magnetic lines of force
act.
12
608The relative permeability of silicon is 0.99837 and that of palladium is
( 1.00692, ) choose the correct option from the following:
A. silicon is paramagnetic and palladium is ferromagnetic
B. silicon is ferromagnetic and palladium is paramagnetic
c. silicon is diamagnetic and palladium is paramagnetic
D. Both are paramagnetic
12
609Which of the following is the use of superconductor?
A. They are used in powerful electromagnets
B. They are used in microwaves
c. They are used in MRI
D. All of the above
12
610A ( 10 mathrm{m} ) long copper wire while remaining in the east-west horizontal direction is
falling down with a constant speed of ( 5.0 mathrm{m} / mathrm{s} . ) If the horizontal component of
the earth’s magnetic field ( 0.30 times )
( 10^{-4} W ) erber ( / m^{2} )
What is the instantaneous value of the
e.m.f induced in water?
A. 0.15 volts
B. 1.5 volts
c. 0.15 mili volts
D. 1.5 mili volts
12
611A short bar magnet has a magnetic moment of ( 0.39 J T^{-1} . ) The magnitude
and direction of the magnetic field produced by the magnet at a distance of ( 20 mathrm{cm} ) from the centre of the magnet
on the equatorial line of the magnet is
A. 0.049 G, N-S direction
B. 4.9 G, S-N direction
c. 0.0195 G, S-N direction
D. ( 19.5 mathrm{G} ), N-S direction
12
612( frac{a}{k} )12
613The ratio of the radii if gyration of a circular disc and a circular ring of same
masses and radii about a tangential axis parallel to their plane is
A. ( sqrt{6}: sqrt{5} )
B. ( 1: sqrt{2} )
c. ( sqrt{5}: sqrt{6} )
D. None of these
12
614A ferromagnetic material heated above its curie temperature. Which one is a
correct statement?
A. Ferromagnetic domains are perfectly arranged
B. Ferromagnetic domains become random
c. Ferromagnetic domains are not influenced
D. Ferromagnetic material changes into diamagnetic materia
12
615A bar magnet is demagnetized by inserting it inside a solenoid of length ( 0.2 m, 100 t u r a s, ) and carrying a current
of ( 5.2 A . ) The coercivity of the bar
magnet is:
A. ( 1200 A / m )
в. ( 2600 A / m )
c. ( 5200 A / j m )
D. ( 285 A / m )
12
616Magnetic field at point ‘P’due to
following current distribution is
A ( cdot frac{mu_{0} I}{pi r^{2}} sqrt{r^{2}-a^{2}} )
В ( cdot frac{mu_{0} i}{2 pi a} )
C ( cdot frac{mu_{0} I}{2 pi r^{2}} sqrt{r^{2}-a^{2}} )
D. ( frac{mu_{0} l a}{2 pi r^{2}} )
12
6176. The variation of magnetic susceptibility (W) with temperature
for a diamagnetic substance is best represented by
(a) o
(b) of
(d)
12
618A bar magnet placed in non-uniform magnetic field experiences.
A. Only torque
B. Only force
c. Both torque and force
D. Neither force not torque
12
619A current of ( 10 mathrm{A} ) is flowing in a wire of
length ( 1.5 mathrm{m} . ) A force of ( 15 mathrm{N} ) acts on it when it is placed in a uniform magnetic field of 2 T. The angle between the magnetic field and the direction of the
current is:
A ( .30^{circ} )
B . ( 45^{circ} )
( c cdot 60^{circ} )
D. ( 90^{circ} )
12
620If a magnet is suspended at an angle ( 30^{circ} )
to the magnetic meridian, the dip needle
makes an angle of ( 60^{circ} ) with the horizontal
The true value of dip is :
A ( cdot tan ^{-1}(2 / 3) )
B ( cdot tan ^{-1}(3 / 2) )
c. ( tan ^{-1}(3) )
D. ( tan ^{-1}(2) )
12
621The coercivity of a small magnet where the ferromagnet gets demagnetized is
( 3 times 10^{3} A m^{-1} . ) The current required to
be passed in a solenoid of length ( 10 mathrm{cm} )
and number of turns ( 100, ) so that the magnet gets demagnetized when inside the solenoid, is:
( A cdot 3 A )
в. ( 6 A )
( c .30 m A )
D. ( 60 mathrm{mA} )
12
622Two poles of same strength attract each other with a force of magnitude ( F ) when
placed at the corners of an equilateral triangle. If a north pole of the same
strength is placed at the third vertex, it experiences a force of magnitude
A. ( F sqrt{3} )
в. ( F )
c. ( F sqrt{2} )
D. ( 2 F )
12
623Assertion
Magnetic lines forms closed loops in
nature.
Reason
Mono-magnetic pole does not exist in
nature.
A. Both Assertion and Reason are correct and Reason is
the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion.
C. Assertion is correct but Reason is incorrect.
D. Both Assertion and Reason are incorrect.
12
624Which of the following figures
represents the magnetic lines of force
due to an isolated south pole?
( A )
B.
( c )
D.
12
625The material for making permanent magnets should have
A. high retentivity, high coercivity
B. high retentivity, low coercivity
c. low retentivity, high coercivity
D. low retentivity, low coercivity
12
626For protecting a sensitive equipment from external magnetic field, it should
be
A. placed inside an iron can
B. placed inside an aluminium can
c. surrounded with fine copper sheet
D. wrapped with insulation around it when passing current through it
12
627Two magnetic poles each of magnetic pole strength ( 16 A m ) are placed at a distance of ( 2 m ) apart. Find magnetic force acting on each pole.
A ( cdot 4 times 10^{-7} N )
В. ( 16 times 10^{-7} N )
c. ( 32 times 10^{-7} N )
D. ( 64 times 10^{-7} N )
12
628A line joining places of same declination
is called
A . agonic
B. isoclinic
c. isodynamic
D. isogonal
12
629The magnetism is minimum . in
a bar magnet.
A. near the ends
B. near the middle
c. at the ends
D. at the middle
12
630A dip of needle shows a dip of ( delta ) when placed in magnetic meridian. Now, the vertical plane in which the needle
moves is rotated by an angle ( alphaleft(<90^{0}right) )
from the place of the magnetic meridian. With what angle the needle
will dip
( A cdotdelta )
( c .=delta )
D. cant be determined
12
631The horizontal component of the flux density of earth’s magnetic field is
( 1.7 times 10^{-5} T . ) The value of the horizontal
component of the intensity of earth’s magnetic field will be:
A ( cdot 24.5 A m^{-1} )
B. ( 13.5 A m^{-1} )
c. ( 1.53 A m^{-1} )
D. ( 0.35 A m^{-1} )
12
632The distance between a north pole of
strength ( 6 times 10^{-3} A m ) and south pole of
strength ( 8 times 10^{-3} mathrm{Am} ) is ( 10 mathrm{cm} . ) The poles
are separated in air. The force between
them:
A ( cdot 4.8 times 10^{-11} N )
В. ( 24 times 10^{-11} N )
( mathbf{c} cdot 48 times 10^{-11} N )
D. ( 24 times 10^{-12} N )
12
633A thin iron ring with mean diameter
( d=50 mathrm{cm} ) supports a winding
consisting of ( N=800 ) turns carrying
current ( boldsymbol{I}=mathbf{3 . 0} boldsymbol{A} . ) The ring has a cross
cut of width ( b=2.0 ) mm. Neglecting the
scattering of the magnetic flux at the gap edges, and using the plot shown in figure above, find the permeability of
iron under these conditions.
12
634A ring is made of a wire having a
resistance ( R_{0}=12 Omega ). Find the points ( A )
and ( mathrm{B} ) as shown in fgure at which a current carrying conductor should be
connected so that the resistance ( R ) of
the sub circuit between these points is
equal to ( frac{8}{3} Omega )
A ( cdot frac{l_{1}}{l_{2}}=frac{3}{8} )
B ( cdot frac{l_{1}}{l_{2}}=frac{1}{2} )
( mathbf{c} cdot frac{l_{1}}{l_{2}}=frac{5}{8} )
D. ( frac{l_{1}}{l_{2}}=frac{1}{3} )
12
635Curie temperature is the temperature above which
(a) a paramagnetic material becomes ferromagnetic
(b) a ferromagnetic material becomes paramagnetic
(c) a paramagnetic material becomes diamagnetic
(d) a ferromagnetic material becomes diamagnetic
(AIEEE 2003)
12
636State True or False.
Magnetic lines of force are closed
continuous curves.
12
637Magnetically aligned atoms in a magnetic material forms a cluster. The cluster is called a:
A. Domain
B. Molecule
c. Pole
D. charge
E. Electron cloud
12
638Discuss the special properties of ferromagnetic materials.12
639Two short magnets of magnetic moment ( 1000 A m^{2} ) are placed as
shown at the corners of a square of side
10 ( c m . ) The net magnetic induction at ( P )
is
A ( .0 .1 T )
B. ( 0.2 T )
c. ( 0.3 T )
D. ( 0.4 T )
12
640Among the following has the
highest retentivity.
A. aluminium
B. steel
c. nickel
D. soft iron
12
641Th direction of magnetic lines of force of
a bar magnet is:
A. from south to north pole
B. from north to south pole
c. across the bar magnet
D. from south to north pole inside the magnet and from north to south pole outside the magnet
12
642Isogonic lines of a magnetic map represent lines joining places with
same
A. ( B ) н
B. dip
c. zero dip
D. declination
12
643Which of the following does not form magnetic element?
( A cdot B H )
в. ( B v )
( c . ) dip
D. declination
12
644Ferromagnetism is not found in
A. conductors
B. semiconductors
c. cobalt
D. gases
12
645Magnetic lines of force :
A. Always intersect.
B. Are closed curves.
C. Tend to crowd far away from the poles of a magnet.
D. Do not pass through vacuum.
12
646( frac{n}{L} )12
647Three identical bars ( A, B ) and ( C ) are
made of different magnetic materials. When kept in a uniform magnetic field, the field lines around them look as
follows:
Make the correspondence of these bars with their material being diamagnetic
( (D), ) ferromagnetic ( (boldsymbol{F}) ) and paramagnetic ( (boldsymbol{P}) )
A. ( A leftrightarrow F, B leftrightarrow P, C leftrightarrow D )
в. ( A leftrightarrow P, B leftrightarrow F, C leftrightarrow D )
c. ( A leftrightarrow D, B leftrightarrow P, C leftrightarrow F )
D. ( A leftrightarrow F, B leftrightarrow D, C leftrightarrow P )
12
648Magnetic lines do not intersect one-
another because:
A. they are at a distance
B. they are in the same direction
C. they are parallel to one another
D. in the point of intersection there will be two direction of the magnetic field, which is impossible
12
649A unit magnetic pole is that pole which
repels an identical pole at a 1 meter distance with a force of
В. ( 10^{-7} N )
( mathbf{c} cdot 10^{-5} N )
D. ( 10^{-4} N )
12
650The temperature at which the domain
structure gets destroyed and ferromagnetic substance is converted into paramagnetic substance is called
as
A. Domain
B. Curie Temperature
c. Rowland
D. Magnetic Field Intensity
12
651The hysteresis cycle for the material of a transformer core is:
A. short and wide
B. tall and narrow.
c. tall and wide
D. short and narrow
12
652Assertion
A disc-shaped magnet is deviated above a superconducting material that has been cooled by liquid nitrogen.
Reason

Superconductors repel a magnet.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
c. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect

12
653Curie temperature is the temperature
above which
A. a paramagnetic material becomes ferromagnetic
B. a ferromagnetic material becomes paramagnetic
C . a paramagnetic material becomes diamagnetic
D. a ferromagnetic material becomes diamagnetic
12
654Soft iron is used for the construction of
electromagnets because for iron
A. the area of hysteresis loops is more
B. coersive force is high.
C. retentivity is high
D. magnetic saturation limits is high and coercivity is low
12
655If the angle of dip at a certain place is
( 45^{circ} ) then the horizontal component ( boldsymbol{H} )
vertical component ( V ) and total
intensity ( I ) of earth’s magnetic field have the correct relationship given by :
A. ( H=sqrt{2} V )
В. ( I=sqrt{2} V )
( mathbf{c} cdot H=2 V )
D. ( H=sqrt{2} H )
12
656The areas under the I-H hysteresis loop and B-H hysteresis loop are denoted by ( A_{1} ) and ( A_{2}, ) then the ratio of ( frac{A_{2}}{A_{2}} ) is given by
( A cdot mu_{0} )
в. ( frac{1}{mu_{0}} )
( c cdot 1 )
D. ( sqrt{mu_{0}} )
12
657State whether True or False:
Hysteresis is the number of lines of force per unit area in a magnetic field.
A. True
B. False
12
658Assertion
Paramagnetic substances get weakly
attracted to a magnet.
Reason
They have tendency to move from a
region of strong magnetic field to weak
magnetic field.
A. Both Assertion and Reason are correct and Reason is
the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is
not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
65966. The dip at a place is d. For measuring it, the axis of the din
needle is perpendicular to the magnetic meridian. If the axis
of the dip needle makes angle with the magnetic meridian
the apparent dip will be given tan 8, which is equal to
(a) tan d cos e
(b) tan 8 sec
(c) tan sin e
(d) tan 8 cosec o
1..
.
c
12
660At a place on Earth, the vertical
component of Earth’s magnetic field is ( sqrt{3} ) times its horizontal component. The angle of dip at this place is
A ( .30^{circ} )
В. ( 60^{circ} )
( c cdot 45^{circ} )
D. ( 0^{circ} )
12
661A circular coil of radius ( 10 mathrm{cm}, 500 )
turns and resistance ( 2 Omega ) is placed with its plane perpendicular to the horizontal component of the earth’s magnetic field It is rotated about its vertical diameter
through ( 180^{circ} ) in 0.25 s. Estimate the
magnitudes of the emf and current
induced in the coil. Horizontal
component of earth’s magnetic field at the place is ( 3.0 times 10^{-5} mathrm{T} )
12
662The B-H curve for a ferromagnet is
shown in the figure. The ferromagnet is placed inside a ling solenoid with 1000
turns/cm.. The current that should be passed in the solenoid to demagnetise
the ferromagnet completely is:
( A cdot 2 m A )
В. ( 1 m A )
( c .3 m A )
D. None of these
12
663Draw the pattern of magnetic field lines
for a bar magnet.
12
664If the vertical component of earth’s magnetic field at a place is ( sqrt{3} ) times the horizontal component, then the value of dip at that place is
A .60
B . 45
c. 30
D. ( 15^{circ} )
12
665A short bar Magnet with its north pole facing North forms a neutral point P in the horizontal plane. If the magnet is rotated by ( 90^{0} ) in the horizontal plane, the net magnetic induction at ( mathrm{P} ) is:
(Horizontal component of earths
magnetic field is ( B_{H} ) )
A. 0
в. ( 2 B_{H} )
c. ( frac{sqrt{5}}{2} B_{H} )
D. ( sqrt{5} B_{H} )
12
666Susceptibility is large and positive for
A. para magnetio
B. diamagnetic
C. ferro magnetic
D. electromagnetic
12
667At a certain temperature, a ferromagnetic material becomes
paramagnetic. What is this temperature called?
12
668Assertion: At high temperature, a ferromagnet becomes a paramagnet. Reason: The ferromagnetic property depends on temperature
A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true and reason is not the correct explanation of assertion.
c. If assertion is true but reason is false.
D. If both assertion and reason are false
12
669A copper rod ( 10 mathrm{cm} ) long rotates 1800
times per minute about an axis passing through one end at a right angle to the rod. A uniform magnetic field of 1 tesla is applied perpendicular to the plane of rotation. The voltage induced between the ends of the rod is
A . ( 0.235 mathrm{v} )
B. ( 0.942 mathrm{V} )
c. ( 2.35 v )
D. zero
12
670Write Sl unit of magnetic dipole
moment.
12
671When a proton is released vest in a room. it starts with an initial
acceleration ( a_{0} ) towards west. When it
is projected towards north with a speed
( v_{0} ) it moves with an initial acceleration
( 3 a_{0} ) toward west. The electric and
magnetic fields in the room are
( mathbf{A} cdot frac{m a_{0}}{e} ) east ( , frac{3 m a_{0}}{e v_{0}} u p )
B. ( frac{m a_{0}}{e} ) east, ( frac{3 m a_{0}}{e_{e 0}} ) down
( mathbf{C} cdot frac{m a_{0}}{e} ) west ( , frac{2 m a_{0}}{e v_{0}} u p )
D. ( frac{m a_{0}}{e} ) west ( , frac{2 m a_{0}}{e_{e v}} d o w n )
12
672A magnetic field is produced by the two
magnets as shown, the magnetic field
is
A. uniform
B. non-uniform and ( N ) is a strong end
C. non-uniform and ( S ) is a strong end
D. uniform and both ( N ) and ( S ) ends are equally strong
12
673Assertion: The product of magnetic susceptibility and absolute temperature for a paramagnetic substance is constant.
Reason: Susceptibility is positive but
very small for paramagnetic substance
A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true and reason is not the correct explanation of assertion.
c. If assertion is true but reason is false
D. If both assertion and reason are false
12
674Assertion
Substances which at room temperature retain their ferromagnetic property for a long period of time are called
permanent magnets.
Reason
Permanent magnet can be made by placing a ferromagnetic rod in a solenoid and passing current through it.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C. Assertion is correct but Reason is incorrect
D. Both Assertion and Reason are incorrect
12
675The core of electromagnet is made of soft iron, because
a) susceptibility of soft iron is very high
b) coercivity of soft iron is very low
A. only a is correct
B. only b is correct
c. both a and b are correct
D. both a and b are wrong
12
676A magnet has a pole strength of 1000 milli amp.m. The magnetic field intensity at a distance of ( 10 mathrm{cm} ) from its North pole
is
( mathbf{A} cdot frac{25}{pi} A / m )
B . ( frac{pi}{25} A / m )
( mathbf{c} cdot frac{100}{pi} A / m )
D ( cdot frac{pi}{100} A / m )
12
677Which of the following best describe the spacing of the field lines?
A. Indicates the strength of the magnetic field
B. Is greatest near the poles
c. Is smallest far away from the poles
D. Indicates the direction of the magnetic field
E. Is the same everywhere around the magnet
12
678Susceptibility of ferromagnetic substance is
( A cdot>1 )
в. ( <1 )
c. zero
D.
12
679The mid points of two small magnetic dipoles of length ( d ) in end-on positions, are separated by a distance ( boldsymbol{x},(boldsymbol{x}>>boldsymbol{d}) )
The force between them is proportional
to ( x^{-n} ) where ( n ) is :
( A )
в.
( c )
( D )
12
680State whether the following statement
is True or False.

The magnetic lines of force around a bar magnet mutually attract each other.

12
681Determine the horizontal component of
the earth’s magnetic field at the
location.
12
682Two short magnets placed along the same axis with their like poles facing each other will repel each other with a
force which varies inversely as
A. Distance
B. Square of distance
c. cube of distance
D. Fourth power of distance
12
683Which of the following is/are correct about magnetic lines of force?
A. Are mere directions
B. Have no physical reality
c. can be used to indicate the direction of the magnetic field at a point
D. All of these
12
684A frog can be levitated in magnetic field produced by a current in a vertical solenoid placed below the frog. This is possible because the body of the frog behaves as
A. Paramagnetic
c. Ferromagnetic
12
685From the following,pick a property that is associated to ferromagnetic
materials only:
A. attracting magnetic substance
B. hysterisis
c. directional property
D. susceptibility independent of temperature
12
686A diamagnetic material in a magnetic
field moves
A. perpendicular to field
B. from stronger to weaker parts of the field
c. from weaker to stronger parts of field
D. None of these
12
687A piece of material moves very slowly towards a pole of magnet. The material
must be
A. Diamagnetic
B. Ferromagnetic
c. Paramagnetic
D. Ferrimagnetic
12
688Susceptibility is small and positive for
A. para magnetic only
B. diamagnetic only
c. ferro magnetic only
D. Both 1 & 3
12
689A ball of superconducting material is dipped in liquid nitrogen and placed near a bar magnet. In which direction will it move then?
A. Away from bar magnet
c. Around the bar magnet
D. Remains constant
12
69056. The magnetic field intensity H at the centre of a long
solenoid having n turns per unit length and carrying a
current I, when no material is kept in it is
(a) Moni
(b) nl
(d) to
12
691A substance is placed in a non uniform magnetic field. It experiences weak force towards the strong field. The substance is ( _{-}-_{-}-_{-}-_{-}-_{-} ) type.
A. Ferromagnetic
c. Paramagnetic
D. None of these
12
692Define the terms:
¡) Declination
ii) Inclination or Dip.
12
693Curie temperature is the temperature
above which
A. a ferromagnetic material becomes paramagnetic
B. a paramagnetic material becomes diamagnetic
C . a ferromagnetic material becomes diamagnetic
D. a paramagnetic material becomes ferromagnetic.
12
694A dip needle shows angle of dip ( tan ^{-1}left(frac{2}{sqrt{3}}right) ) in a vertical plane which is
at an angle of ( 60^{0} ) with the magnetic meridian. The real dip at the place is
then
A ( cdot 0^{circ} )
B . ( 45^{circ} )
( c cdot 30^{0} )
D. ( 90^{circ} )
12
695paramagnetic substance will look like
( A )
B.
( c )
D.
12
696The real angle of dip, if a magnet is
suspended at an angle of ( 30^{0} ) to the
magnetic meridian and the dip needle
makes an angle of ( 45^{0} ) with horizontal is :
( ^{A} cdot tan ^{-1}left(frac{sqrt{3}}{2}right) )
B ( cdot tan ^{-1}(sqrt{3}) )
( ^{mathbf{c}} cdot tan ^{-1}left(frac{1}{2}right) )
D ( cdot tan ^{-1}left(frac{2}{sqrt{3}}right) )
12
697The horizontal and vertical components of the Earth’s magnetic field at a place
are each equal to 0.35 gauss. Find the angle of dip at the places.
12
698The earth’s magnetic field at the
equator is approximately ( 0.4 G . ) The earth’s dipole moment is :
( left(boldsymbol{R}_{e}=mathbf{6 . 4} times mathbf{1 0}^{mathbf{6}} boldsymbol{boldsymbol { m }}right) )
A ( cdot 4 times 10^{2} A m^{2} )
B . ( 1.05 times 10^{23} mathrm{Am}^{2} )
c. ( 4 times 10^{-5} mathrm{Am}^{2} )
D. ( 1.05 times 10^{-20} mathrm{Am}^{2} )
12
699a bar magnet is made to fall through a
long vertical copper tube .The speed (v) of the magnet as a function of time (t)
is best represented by
( A )
B.
( c )
( D )
12
700A beam has intensity ( 2.5 times 10^{14} W m^{-2} )
The ratio of electric and magnetic fields in the beam is
A . ( 3.44 T )
в. ( 3.14 T )
c. ( 1.004 T )
D. 1.447
12
701A watch glass containing some powdered substance is placed between the pole
pieces of a magnet. Deep concavity is observed at the center. The substance in
the watch glass is (assume poles are far)
A. iron
B. chromium
c. carbon
D. woodd
12
702A sensitive magnetic instrument can be
shielded very effectively from outside
magnetic fields by placing it inside a box
of:
A. wood
B. plastic
C. metal of high conductivity
D. soft iron of high permeability
12
703A charge is projected with a velocity of ( 10^{5} m / s . ) In a perpendicular magnetic field. Find the magnetic of a transverse electric field if if moves undeflected
( left(B=4 * 10^{-5} Tright) )
A . ( 4 mathrm{N} / mathrm{C} )
в. ( 4 times 10^{-2} mathrm{N} / mathrm{C} )
c. ( 24 times 10^{-2} N / C )
D. not possible
12
704What are permanent magnets? Give one example.12
705A small, magnetized sphere A of pole strength ( m ) is counter-poised by a pan in a balance. Another magnetised sphere B of the same mass as ( A ) is placed below ( A ) so that their centres are at a distance
( 1 mathrm{cm} . ) If ( mathrm{A} ) and ( mathrm{B} ) are unlike poles of same strength and to restore counter the weight in the pan is increased by ( 500 g m ) the pole strength of each sphere is:
A ( .1 .4 A m )
B. ( 9.8 A m )
c. ( 0.7 A m )
D. ( 70 A m )
12
70643. Which of the following is most suitable for the core of
electromagnets?
(a) Soft iron
(b) Steel
(c) Copper-nickel alloy (d) Air
12
707What are the changes observed at the transition temperature in
superconductors?
12
708A bar magnet is ( 0.10 mathrm{m} ) long and its
pole strength is ( 120 A ) m. Find magnitude of magnetic field at a point
on the its axis at a distance ( 20 mathrm{cm} ) from
¡t.
12
709Magnetic lines of force always cross
each other. Is the given statement true or false? Justify.
12
710The magnetic susceptibility of a
paramagnetic material at ( -73^{0} ) is
( 0.0075, ) its value at ( -173^{0} mathrm{C} ) will be
A . 0.0045
B. 0.0030
c. 0.015
D. 0.0075
12
711Permanent magnets should have
A. High retentivity and low coercivity.
B. Low retentivity and high coercivity.
C. High retentivity and high coercivity.
D. Low retentivity and low coercivity.
12
712Which one of the following statements
best describes the nature of the field
lines due to a bar magnet?
A. Field lines start from the north pole and end on the south pole. Any number of field lines can pass through a point
B. Field lines start from the north pole and end on the south pole. Only one field line passes through a point
C. Field lines are continuous lines passing inside and outside the magnet. Only one field line passes through a point
D. Field lines are continuous lines passing inside and outside the magnet. Any number of field lines can pass through a point
12
713The resultant magnetic field at the center of a bar magnet is zero.
A. True
B. False
12
714Magnetic dipole moment is a:
A. Scalar quantity
B. Vector quantity
C. Constant quantity
D. None of these
12
715Domain formation is the necessary
feature of
A. ferromagnetism
B. diamagnetism
c. paramagnetism
D. all of these
12
716Curie temperature is the temperature
above which
A. Paramagnetic material becomes ferromagnetic material
B. Ferromagnetic material becomes diamgnetic material
C. Ferromagnetic material becomes paramagnetic material
D. Paramagnetic material becomes diamagnetic material
12
717The magnetic field at point ( C ) as shown in
the figure is:
( A )
[
frac{mu_{0} M_{0}}{2 pi r_{0}^{3}}
]
B. ( frac{sqrt{2} mu_{0} M_{0}}{2 pi r_{0}^{3}} )
C. zero
D. ( frac{sqrt{2} mu_{0} M_{0}}{4 pi r_{0}^{3}} )
12
71842. When a ferromagnetic material is heated to temperature
above its Curie temperature, the material
(a) is permanently magnetized
(b) remains ferromagnetic
(c) behaves like a diamagnetic material
(d) behaves like a paramagnetic material
12
719The magnetic induction at a distance d
from the magnetic pole of the unknown strength ( m ) is ( B ). If an identical pole is now placed at a distance of ( 2 mathrm{d} ) from the first pole, the force between the two poles is
A. ms
B. ( frac{m B}{2} )
( mathbf{c} cdot frac{m B}{4} )
D. 2mB
12

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