Magnetic Effects Of Electric Current Questions

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Magnetic Effects Of Electric Current Questions

List of magnetic effects of electric current Questions

Question NoQuestionsClass
1In an electrical circuit two resistors of 2
( Omega ) and ( 4 Omega ) respectively are connected in series to a ( 6 mathrm{V} ) battery. The heat dissipated by the ( 4 Omega ) resistor in 5 s will be
A . 5 J
B. 10
c. 20
D. 30
2Choose the correct statement from the
This question has multiple correct options
A. Soft iron is used as the core of transformer.
B. The strength of an electromagnet increases when the current in the coil is increased.
C. An electric bell works on the principle of an electromagnet.
D. The direction of a magnetic field due to current in a straight conductor is obtained using right hand grip rule.
3Heat produced in a resistor when current is passed through it depends
A. Current only
B. Time only
c. Current and time
D. None of these
4Alternating current is one which
changes in its :
A. direction
B. magnitude
c. magnitude and direction both
D. none
5The current in an AC circuit is
represented by ( i=5 sin left(300 t-frac{pi}{4}right) )
where, t is in seconds and current is in amperes. Then, the frequency of AC is
( A cdot 50 mathrm{Hz} )
B. 47.75 Hz
( c cdot 30 ) Нz
D. 25 Hz
6The element of electric heater is made
A. Iron
B. Nichrome
c. copper
D. Gold
7A bulb is connected to an ideal battery
of emf ( 10 mathrm{V} ) so that the resulting current is ( 10 mathrm{mA} ). When the bulb is connected to
( 220 mathrm{V} ) mains (ideal), the current is 50
mA. choose the correct alternative
A. the resistance of the bulb is 1 k ohm and in the second case, it is ( 4.4 mathrm{k} ) ohm
B. it is not possible since ohm’s law is not followed
c. the increase in resistance is due to heating of the filament of the bulb when it is connected to ( 220 mathrm{v} ) main
D. none of these
8Write daily life uses of heating effect of electric current10
9Which of the following does not electrical power in circuit?
( mathbf{A} cdot I^{2} R )
B . ( I R^{2} )
c. ( V I )
D. ( frac{V^{2}}{R} )
10One unit of electric energy is equal to:
A. One kilowatt hour
B. one watt hour
c. 100 Joules
D. none of these
11Why are transmission losses so crucial
that electrical power systems are
designed to work on Alternating
A. Electrical power systems are not very efficient for transmission of power
B. It is a practice to use AC over DC
C. AC networks are easier to handle than DC Networks and constructional setup cost is really high in DC
D. since, power stations are very far away from destinations, transmission has to be done over long distances and losses add up over the distance
12Either a fuse or a circuit-breaker can be
used to protect electrical cables from
large currents that could cause
When a fuse is used, where should it be
connected, and when a circuit-breaker
is used, where should it be connected?
A. Position of fuse ( -X ), Position of circuit-breaker ( -X )
B. Position of fuse – ( X ), Position of circuit-breaker – ( Y )
c. Position of fuse ( -Y ), Position of circuit-breaker ( -X )
D. Position of fuse – ( Y ), Position of circuit-breaker – ( Y )
13An alternating voltage ( boldsymbol{E}= ) ( 200 sqrt{2} sin (100 t) ) is connected to 1
microfarad capacitor through ( A C ) ammeter. The reading of ammeter shall be
( A cdot 10 m A )
B. ( 20 mathrm{mA} )
c. ( 40 mathrm{mA} )
D. ( 80 mathrm{mA} )
14Define alternating current and explain
working of the device which produces it. Draw labelled diagram. Describe the change in direction of current.
15( 4 sqrt{2} m ) and breadth ( 4 m ) carrying a
current of ( 5 A ) in the anti-clockwise
direction is placed in the xy-plane. The
magnitude of the magnetic induction
field vector ( B ) at the intersection of the
diagonal is ( left(U s e u_{0}=4 pi xright. )
( left.10^{-7} N A^{-2}right) )
A ( .1 .2 times 10^{-6} T )
B . ( 1.2 times 10^{-5} T )
c. ( 2.4 times 10^{-6} T )
D. ( 2.4 times 10^{-5} T )
E ( .1 .2 times 10^{-7} T )
16State some characteristics of magnetic
field due to a Current through a Straight Conductor.
17Find the total current that passes
through the circuit. Find the heat
generated across the each resistor:
18What is the voltage of the electricity that is generally supplied to a house?
( mathbf{A} cdot 400 V )
B. ( 200 mathrm{V} )
( mathbf{c} cdot 220 V )
D. ( 260 V )
19An electric bulb is rated at ( 220 mathrm{V}, 100 mathrm{W} )
What safe current can be passed through it ?
( mathbf{A} cdot 2 cdot 20 A )
B . ( 3.50 A )
c. ( 0.45 A )
D. ( 0.50 A )
20A lamp is marked ( 60 mathrm{W}, 220 mathrm{V} ). If it
operates at ( 200 mathrm{V} ), the rate of consumption of energy will
A. decrease
B. increase
c. remain unchanged
D. first increase then decrease
21A magnetic field lines due to a straight wire carrying a current are
A. Straight
B. Circular
c. Parabolic
D. Elliptical
22Two horizontal metal plates having a
potential difference of ( 800 mathrm{V} ) are ( 0.02 mathrm{m} ) apart. A particle of mass ( 1.92 times ) ( 10^{-15} mathrm{kg} ) is suspended in equilibrium
between the plates. Ife is the elementry charge, then charge on the particle is:
( A )
B . 3 e
c. ( 6 mathrm{e} )
D. ( 8 mathrm{e} )
23How should the electric lamps in a
building be connected?
An alternating current does not show
any magnetic effect.
Alternating current does not vary with time
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
25f current ( boldsymbol{I}_{1}=mathbf{3} boldsymbol{A} sin omega boldsymbol{t} ) and ( boldsymbol{I}_{2}= )
( 4 A cos omega t, ) then ( I_{3} ) is
A ( cdot 5 a sin left(omega t+53^{circ}right) )
B. ( 5 a sin left(omega t+37^{circ}right) )
c. ( 5 a sin left(omega t+45^{circ}right) )
D. ( 5 a sin left(omega t+30^{circ}right) )
26An electric kettle is rated ( 2.5 k W, 250 V )
What is the cost of running the kettle
for two hours at Rs. 5.40 per unit?
A. ( R s .17 .00 )
B. ( R s .27 .00 )
c. ( R s .26 .00 )
D. ( R s .16 .20 )
27An electric iron uses a power of ( 1320 W ) when set to higher temperature. If set to lower temperature one third of higher
temperature current is used. If iron is
connected to a potential of ( 220 V ), then power used to lower temperature is
( mathbf{A} cdot 220 W )
в. ( 440 mathrm{W} )
c. ( 660 W )
D. ( 880 W )
28A given resistor cannot carry currents exceeding 20 A, without exceeding its maximum power dissipation ratings. By forced air cooling suppose that we increase the rate at which heat can be
carried by a factor of ( 2 . ) Now the maximum current that the resistor can
carry is
A. ( 10 A )
В. ( 20 sqrt{2} A )
( c cdot 30 sqrt{2} A )
D. ( 40 A )
29Choose the incorrect statement:
A. Flemings right-hand rule is a simple rule to know the direction of induced current
B. The right-hand thumb rule is used to find the direction of magnetic fields due to current carrying conductors
C. The difference between the direct and alternating currents is that the direct current always flows in one direction, whereas the alternating current reverses its direction periodically
D. In India the AC changes direction after every ( frac{1}{50} ) second
30The potential of neutral wire is:
A. ov
B. 300V
c. ( 220 v )
D. 1000v
31Name the switch/switches to be closed
so as to light all the three lamps
( A cdot 2 ) and
B. 1 and 3
c. only 2
D. 1 and
32Commonly used heating element are
made of:
A. Iron
B. Manganese
c. Nichrome
D. Platinum
33Calculate the value of current ( i ), in the
given electric circuit:
34n the circuit shown in the figure, find
the current in ( 45 Omega )
ugure, una tne current in
A. ( 4 A )
В. 2.5
( c .2 A )
D. None of these
35A coil of self inductance ( 10 m H ) and
resistance ( 0.1 Omega ) is connected through a switch to a battery of internal resistance ( 0.9 Omega ) After the switch is closed, the time taken for the current to attain ( 80 % ) of the saturation value is :
(Take ( l n 5=1.6) )
A . ( 0.103 s )
B. ( 0.016 s )
c. ( 0.002 s )
D. ( 0.324 s )
36State the observations made by
Oerested on the basis of his
experiments with current carrying conductor.
37wire/is/are connected
directly to the electric meter.
A. line wire
B. earth wire
c. neutral wire
D. all
38Net magnetic field at the centre ofthe
circle 0 due to a current carrying
loop as shown in figure is ( left(boldsymbol{theta}<mathbf{1 8 0}^{circ}right) )
A. zero
B. perpendicular to paper inwards
C. perpendicular to paper outwards
D. is perpendicular to paper inwards if ( theta leq 90^{circ} ) and
perpendicular to paper outwards if ( 90^{0} leq theta<180^{circ} )
39The potential difference between points A and B of adjoining figure is :
A. ( 2 / 3 V )
B. ( 8 / 9 V )
c. ( 4 / 3 V )
D. ( 2 V )
40Calculate combined resistance.10
41What is an AC generator? Obtain an expression for the sinusoidal emf induced in the cell of ac generator,
rotating with a uniform angular speed in a uniform magnetic field.
42The relation between an ac voltage source and time in Sl units is ( V= )
( 120 sin (100 pi t) cos (100 pi t) V )
The value of peak voltage and frequency will be respectively:
A. ( 120 mathrm{V} ) and ( 100 mathrm{Hz} )
B. ( frac{120}{sqrt{2}} mathrm{V} ) and ( 100 mathrm{Hz} )
c. ( 60 mathrm{V} ) and ( 200 mathrm{Hz} )
D. ( 60 mathrm{V} ) and ( 100 mathrm{Hz} )
43A step-up transformer operates on a ( 230 mathrm{V} ) line and a load current of ( 2 mathrm{A} ). The ratio of primary and secondary
windings is ( 1: 25 . ) Then the current in
the primary is?
A . 25 A
B. 50 A
c. 15 A
D. 12.5 A
44Which one of the following heater element is used in electric press
A. Copper wire
B. Nichrome wire
c. Lead wire
D. Iron wire
45State one advantage of using a.c. over
46Magnetic lines of force due to a long straight conductor carrying current are
A. straight lines
B. elliptical
c. circular
D. parabolic
47Why is the series arrangement not used for domestic circuits?10
48How much current is drawn by the primary of a transformer connected to ( 220 V ) supply when it delivers power to
a ( 110 V-550 W ) refrigerator?
49Which of the following is not a chemical cell
A. Simple voltaic cell
B. Leclanche cell
c. Daniel cell
D. Solar cell
50Household electrical appliances are joined using combination
of resistors
A. Parallel
B. Alternating
c. continuous
D. Series
51In a circular current-carrying conductor,
the face of the coil towards the observer
behaves like a south pole if the current
A. In clockwise direction
B. In anticlockwise direction
C. In alternating clockwise and anticlockwise direction
D. First in anticlockwise for some time then in clockwise
52Switch is always connected to the
A . live
B. neutral
c. ground
D. live and ground
53Define Electromagnetism
A. The study of attraction or repulsion between two magnets is called electromagnetism
B. The study of electric effects due to magnetic interaction is called electromagnetism
C. The study of magnetic effects produced due to electric current is called electromagnetism
D. The study of magnetic effects produced due to electric charge is called electromagnetism
54Why is parallel arrangement used in
domestic wiring?
A. For getting same potential difference across each electrical appliance.
B. For getting different potential difference across each electrical appliance.
C. For getting high potential difference across each electrical appliance.
D. For getting low potential difference across each electrical appliance.
55Two dissimilar bulbs are connected
in series, which bulb will be brighter?
A. low resistance bulb
B. more resistance bulb
c. high current pass bulb.
D. low current pass bulb
56In the given circuit diagram the ratio of
potential difference across 3 ohm and 4
ohm resistance is ( frac{3}{4} . ) The unknown
resistance ( boldsymbol{R} ) is:-
A. 8.0 ohm
B. 2.0 ohm
( c .4 .5 ) ohm
D. 7.0 ohm
57Which of the following is/are energy
efficient products?
This question has multiple correct options
A. Tube lights
B. Bulbs
c. LEDs
58A house is fitted with 4 lamps 60 w each, 2 fans rated 100 w each, an electric kettle rated 2KW. If the energy
( operatorname{costs} ) Rs. 5.50 per ( mathrm{KWh} ), calculate the monthly bill (of 30 days) for running the appliances for 5 hours a day.
59An electric bulb works on the principle
A. Archimedes
B. heating effect of current
c. magnetic effect of current
D. none of these
60The consumption of electrical energy in the house is measured in terms of:
A. Kilowatt hour
B. Watt hour
c. Joules
D. Kilo joules
61An ideal choke takes a current of ( 8 A )
when connected to an a.c source of 100
volt and 50 Hz. A pure resistance under
the same conditions takes a current of
10A. If two are connected in series to an
a.c. Supply of ( 150 mathrm{V} ) and ( 40 mathrm{Hz} ), then the current in the series combination of
above resistor and conductor is:
62In the following diagram, the potentials
is ( P ) and ( Q ) are
A ( .40 V,-60 V )
в. ( 60 V,-40 V )
( mathbf{c} cdot 40 V, 60 V )
D. ( 60 V, 40 V )
63At what voltage and frequency is the electric power generated at the power generating station?
( mathbf{A} cdot 15 k V, 50 H z )
в. ( 11 k V, 100 H z )
c. ( 11 k V, 50 H z )
D. ( 11 k V, 500 H z )
64Potential difference of ( 220-250 mathrm{V} ) is
present between
A. Earth wire and neutral wire
B. Live wire and earth wire
c. Live wire and neutral wire
D. B and c both
65( ln ) an ( A C ) circuit, the instantanceous
emf and current are given by
( e=100 sin 30 t, i=sin left(30 t frac{pi}{4}right) )
In one cycle of ( A C, ) the average power consumed by the circuit and the wattles current are, respectively
A. 50,0
B. 50,10
c. ( frac{1000}{sqrt{2}}, 10 )
D. ( frac{50}{sqrt{2}}, 0 )
66The supply voltage to room is 120 ( V ). The
resistance of the lead wires is ( 6 Omega . ) A
( 60 W ) bulb is already switched on. What
is the decrease of voltage across the bulb, when a ( 240 W ) heater is switched
on in parallel to the bulb?
A . zero
в. 2.9 volt
c. 13.3 volt
D. 10.04 Volt
67The essential requirements for a good heating element are
A. High resistivity and low melting point
B. High resistivity and high melting point
C. Low resistivity and low melting point
D. Low resistivity and high melting point
68calculate the current through a ( 60 mathrm{W} ) lamp rated for ( 250 mathrm{V} ). if the line voltage falls to ( 200 mathrm{V} ), how is the power consumed by the bulbs affected?10
69The amount of heat produced in a wire depends on its material-
A. Length
B. Thickness
c. Length and thickness
D. None of these
70In an ac circuit the instantaneous
values of current and applied voltage
are respectively ( i= )
( 2(A m p) sin left(250 pi s^{-1}right) t ) and ( epsilon= )
( (10 V) sin left[left(250 pi s^{-1}right) t+frac{pi}{3}right] . ) Find the
power drawn from the source at ( t= )
( frac{2}{3} m s )
71The most important safety method used for protecting home appliances from short circuiting or overloading is
A. earthing.
B. use of fuse
c. use of stabilizers
D. use of electric meter.
72State whether true or false:
The magnetic polarity of an electromagnet does not change with the change in the direction of current in its coil.
A. True
B. False
73Strong magnetic field produced inside a solenoid can be used to magnetise a
A. piece of magnetic material
B. soft iron
( c . ) both
D. none
74Which of the following materials is best suited as the core of an electromagnet
A. steel
B. Iron
c. Alnico
D. Magnetite
75The direction of current in the coil at
one end of an electromagnet is clockwise. This end of
the electromagnet is.
A. north pole
B. south pole
c. east pole
D. west pole
76In the direct current
A. The direction of current is always positive
B. The direction of current is always negative
C. The direction of current changes constantly
D. The direction of current is always in the same direction.
77Two lamps, one rates ( 100 mathrm{W} ; 220 mathrm{V} ), and
the other ( 60 mathrm{W} ; 220 mathrm{V} ) are connected in parallel to electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is ( 220 mathrm{V} )
78An air conditioner is rated
( 240 V, 1.5 k W . ) The air conditioner is
switched on for 8 hours each day. How much electrical energy is consumed in
30 days?
( mathbf{A} cdot 360 k W h )
B. ( 8.64 mathrm{kW} ) h
( mathbf{c} cdot 120 k W h )
D. ( 240 mathrm{kW} ) h
79The element of an electric heater is
made of :
A. Tin
B. Copper
c. Nichrome
D. Tungsten
80The outlets in your home provide.
A. Direct current
B. Alternating current
C. Electric discharge
D. Static Electricity
81Choose the incorrect option: Expansion during heating:
A. occurs only in a solid
B. increases the density of the material
c. decreases the density of the material
D. occurs at the same rate for all liquids and gaseous
82A bulb marked ( 12 V, 24 W ) operates 12
volt battery for 20 minutes. The current flowing through it is :
A ( .2 A )
в. ( 0.5 A )
( c cdot 1 A )
D. ( 1.5 A )
83The magnitude of a magnetic field at
the centre of a circular coil of radius ( R )
having ( N ) turns and carrying a current
can be doubled by changing
( mathbf{A} cdot I ) to ( 2 I ) and ( N ) keeping ( R ) unchanged
B. ( N ) to ( frac{N}{2} ) and keeping ( I ) and ( R ) unchanged
C . ( N ) to ( 2 N ) and ( R ) keeping ( 2 R ) keeping/unchanged
D. ( R ) to ( 2 R ) and ( l ) to ( 2 I ) keeping ( N ) unchanged
E . ( I ) to ( 2 I ) and keeping ( N ) and ( R ) unchanged
84Electrical welding works on principle of:
A. continuity equation of electric current
B. heating effect of electric current
C. heating effect of exothermic reactions
D. none of the above
85Write the equation of 25 cycle current
sine wave having rms value of ( 30 A )
86Mark the incorrect statement.
A. In our homes, we receive supply of electric power through a main supply
B. Red insulation cover, is called live wire
C. The earth wire, has insulation of green colour
D. None
87Statement 1: Electric current (flow of
electrons) creates heat in the resistor.
Statement 2: Heat in the resistor is
created according to the rule of energy conservation.
Explain Statement 1 with the help of
Statement 2.
88The kilowatt hour is the unit of10
89Mark the correct reason/s why
nichrome is used for making heating element of electrical appliances.
A. Nichrome does not oxidize
B. Nichrome doesn’t burn easily at high temperatures as it has higher melting and boiling point than metals
C. Nichrome has higher resisistivity and consequently a higher resistance
D. All
90Find the number of electrons
transferred between two points kept at a potential difference of ( 20 mathrm{V}, ) if 401 of
work is done

Name the colorless transporting fluid found in humans

91A light bulb is rated at ( 100 mathrm{W} ) for a ( 220 mathrm{V} )
supply. Find the peak voltage of the
92Dry cell is a source of
A. Direct current
B. Alternating current
C. Can be used as direct current source or alternating current source
D. Cant say
93A current is flowing in electricity line towards north, the direction of magnetic field at a point which is just below the line is :
A. towards north
B. towards south
c. towards east
D. towards west
94Which statement is wrong from the
A. The earthing wire is green coloured.
B. In India, current flowing through wire is ( A C ) and its frequency is ( 50 mathrm{Hz} )
C. In India, voltage between two wires is ( 110 V )
D. T.V., Tublight, bulbs are connected with ( 5 A ) line.
95How is an electromagnet different from a permanent magnet?10
96In case of A.C, circuit, Ohm’s law holds
good for
a) Peak values of voltage and current
b) Effective values of voltage and
c) Instantaneous values of voltage and
A. only a is true
B. only a and b are true
c. only c is true
D. a, b anc c are true
97In a city, electricity costs ( $ 0.12 ) per kilowatt-hour. A bulb of 150-watt
operates for 5 hours. Calculate the cost
of electricity which is consumed by the bulb.
A. ( $ 0.009 )
в. $0.09
c. ( $ 0.90 )
D. $9.00
E. ( $ 90.00 )
98The electric current passing through a metallic wire produces heating because
A. collisions of conduction electrons with each other
B. collisions of the atoms of the metal with each other
c. the energy released in the ionisation of the atom of the metal
D. collisions of the conduction electrons with the atoms of the metallic wire
99At what voltage is the electric power from generating station transmitted?
A ( .200 k V )
В. ( 11 k V )
( mathbf{c} cdot 220 V )
D. ( 220 k V )
100Nidhi has two bulbs connected across
two cells in a simple circuit as shown.
How can she make the bulbs glow
A. Replace one cell with a piece of chalk.
B. Replace one cell with a piece of wire.
C. Replace one bulb with a piece of wire.
D. Replace one bulb with another cell.
101On which principle A.C generator
102Mica is used in electrical appliances
such as electric iron because mica is
A. a good conductor of heat but a bad conductor of electricity
B. a bad conductor of heat but a good conductor of electricity
C. a good conductor of heat as well as electricity
D. a bad conductor of heat as well as electricity
103An electric heater consists of a
nichrome coil and runs under ( 220 V )
consuming ( 1 k W ) power. Part of its coil
burned out and it was reconnected after
cutting off the burnt portion, The power
it will consume now is:
A. More than ( 1 k W )
B. Less that ( 1 k W ), but not zero
( mathrm{c} .1 mathrm{kW} )
D. ( 0 k W )
104Name any six domestic appliances
based on the heating effect of electric
105A multimeter reads a voltage of a certain A.C. source as ( 100 mathrm{V} ). What is the peak value of voltage of A.C. source?
A . 200
B. 100 V
c. ( 141.4 mathrm{v} )
D. 400
106State whether given statement is True or False

An alternating current cannot be used for electroplating.
A. True
B. False

107A current of ( 0.2 A ) flows through a wire whose ends are at a potential difference
of ( 15 V . ) The heat energy produced in 1
minute will be
( mathbf{A} cdot 60 J )
в. ( 120 J )
( c .180 J )
D. ( 90 J )
108The charge flowing through a resistance ( R ) varies with time ( t ) as ( Q=a t-b t^{2} )
where ( a ) and ( b ) are positive constants.
Calculate the total heat produced in ( R )
109One metal wire is kept in east-
west direction. ( I ) is the current flow
due west. Then, due to magnetic field ( vec{B} ) of the earth on the wire is in the
A. downward
B. Upwarddardpwardd
c. north
D. south
110Three resistors of values ( 2 Omega, 4 Omega, 6 Omega ) are connected is series. The equivalent
resistance of combination of resistors
111The unit in which we pay the cost of electricity is
A. kilowatt hour
B. watt hour
c. joules
D. ergs
112What is the frequency of A.C. in India?10
113Why are in the household electric
circuits the electric appliances
(instruments) connected in parallel combination?
114Distinguish between the term overloading and short circuiting as
used in domestic circuits
115Which is or are the correct for filament
of bulb?
This question has multiple correct options
A. Low melting point
B. High melting point
c. Made of tungsten
D. Made of nichrome
116An electric bulb is marked ( 200 vee, 100 W )
Calculate electrical resistance of its
filament. If five such bulbs are
connected in series to a ( 200 mathrm{V} ) supply, how much current will flow through them?
117Three resistors are connected to a ( 6 mathrm{V} )
battery as shown in the figure given
Calculate the potential difference
across the ( 7.2 Omega ) resistor
118A filament bulb ( 500 mathrm{W}, 100 mathrm{V} ) is to be used in a ( 230 mathrm{V} ) main supply. When a resistance ( R ) is connected in series, it
works perfectly and the bulb consumes ( 500 mathrm{W} ). The value of ( mathrm{R} ) is :-
A . ( 26 Omega )
B. 13Omega
c. ( 236 Omega )
D. ( 46 Omega )
119An electrical device draws ( 2 mathrm{kW} ) power from ac mains voltage ( 223 mathrm{V}(mathrm{rms}) . ) The current differs lags in phase by ( phi= )
( tan ^{-1}[]-frac{3}{4}[mathbb{1}] ) as compared to voltage. The
resistance ( R ) in the circuit is
A . ( 15 Omega )
в. 20 ( Omega )
( c .25 Omega )
D. 30 ( Omega )
120A centre tapped transformer is rated 12
0-12 V. The peak voltage obtained is
A . 12 v
B. ( frac{12}{sqrt{2}} V )
( mathrm{c} cdot 12 sqrt{2} V )
D. ( 24 V )
E ( .24 sqrt{2} V )
121A metal plate can be heated by
A. passing either a direct or alternating current through the plate.
B. placing in a time varying magnetic field.
c. placing in a space varying magnetic field, but does not vary with time.
D. both
(a) and
(b) are correct
122The maximum current which can flow
through a fuse without melting it is called its
A. potential
B. power
c. rating
D. capacity
123A steady P.D. of ( 10 V ) produces heat at a
rate of ( ^{prime} x^{prime} ) in a resistor. The peak value of A.C. voltage which will produce heat at the rate of ( x / 2 ) in the same resistor
A . ( 5 V )
B. ( 5 sqrt{2} v )
( c .10 V )
D. ( 10 sqrt{2} mathrm{v} )
124A lamp rated ( 100 W ) at ( 22 V ) is connected to the main electric supply.
What current is drawn from the supply line if the voltage is ( 220 V )
125Name the device used to increase the
voltage at the generating station.
A. Transformer
B. Capacitor
c. Diodes
D. None of the above
126Voltmeter is an instrument used to
A . Electric current
B. Electric charge
c. Resistance
D. Potential difference
127Which part of the bulb is an insulator?
( A )
( c cdot R )
128State four most common electrical
appliances based on heating effect of electric current. Why do we use finely heated platinum wire in surgery?
129A filament bulb ( (500 W, 100 V) ) is to be
used in a ( 230 mathrm{V} ) main supply. When a resistance ( R ) is connected in series, it works perfectly and the bulb consumes ( mathbf{5 0 0} boldsymbol{W} ). The value of ( boldsymbol{R} ) is.
A . ( 13 Omega )
B . ( 230 Omega )
c. ( 46 Omega )
D. 26 Omega
130Two bulbs, one of ( 200 W ) and the other
of ( 100 W, ) are connected in series with a
( 100 V ) battery which has no internal
resistance. Then,
A. The current passing through the ( 200 W ) bulb is more than that through the ( 100 mathrm{W} ) bulb
B. The power dissipation in the ( 200 W ) bulb is less than that In the ( 100 mathrm{W} ) bulb
c. The voltage drop across the ( 200 W ) bulb is more than that across the ( 100 mathrm{W} ) bulb
D. The power dissipation In the ( 100 W ) bulb is more than that in the ( 200 mathrm{W} ) bulb
131The wire having a black plastic covering
is a
A. live wire
B. neutral wire
c. earth wire
D. none of these
132All power entering a house enters via
A. Electricity Meter
B. Various loads in house
C. Electricity board motor
D. Potential Barrier
133Name two special characteristics of a
heater coil.
134The electrical appliances in a house are
connected in :
A. series
B. parallel
c. either in series or parallel
D. both in series and parallel
135Two identical parallel plate capacitors are connected in series and then joined
with a battery of ( 100 ~ V . A ) sheet of
dielectric constant 4.0 is inserted
between the plates of second capacitor. The potential difference across the
capacitors will be respectively.
( mathbf{A} cdot 50 V, 50 V )
B . ( 80 mathrm{V}, 20 mathrm{V} )
c. ( 20 V, 80 V )
D. ( 75 V, 25 V )
136An electric oven of ( 2 mathrm{kW} ) power rating is operated in a domestic electric circuit
that has a current rating of 5A. If the supply voltage is ( 220 mathrm{V} ), what result do you expect?
A . circuit will be breaked
B. fuse will blow
( c . ) both
D. none
137If four resistances, each of value 1 ohm,
are connected in series, what will be the
resultant resistance?
( A . ) 3 ohm
B. 4 ohm
c. 5 ohm
D. 2 ohm
138A resistance of ( 20 Omega ) is connected to a
source of an alternating potential ( boldsymbol{V}= ) ( 220 sin (100 pi t) . ) The time taken by the
current to change from the peak value
to rms value, is
A . ( 0.2 s )
B. ( 0.25 s )
c. ( 2.5 times 10^{-2} s )
D. ( 2.5 times 10^{-3} s )
139A washing machine rated ( 300 W ) is operated for one hour/day. If the cost of a unit is Rs 3.00 then the cost of the
energy to operate a washing machine for the month of March is
A ( . ) Rs 25.60
B . ( R s 27.50 )
c. ( R s 27.90 )
D. ( R s 26.90 )
140If the current is flowing through a ( 10 Omega ) resistor, then in which case the
maximum heat will be generated?
A. 5 ampere in 2 minutes
B. 4 ampere in 3 minutes
c. 3 ampere in 6 minutes
D. 2 ampere in 5 minutes
141Two bulbs of ( 100 mathrm{W} ) and ( 40 mathrm{W} ) are
connected in series. The current
through the 100 W bulb is 1A. The
current through the 40 W bulb will be
A ( .0 .4 A )
в. ( 0.6 A )
( c .0 .8 A )
D. ( 1 A )
142Which of the following is a source of direct current.
A . Cell
B. Electromagnet
c. Bulb
D. Switch
143A moving charge produces
A. Neither electric field nor magnetic field
B. Electro-static field only
C. Magnetic field only
D. Both magnetic and electro-static field
144The frequency of A.C mains in India is
A. ( 30 c / s )
B. ( 50 c / s )
( mathbf{c} cdot 60 c / s )
D. ( 120 c / s )
145Why are wires coated with plastic
( A ). to make it a bit decorative
B. to make it more durable
C. it order to make them distinguishable
D. to make it shock free
146State whether given statement is True or False

The designation rms means repetitions measured per second.
A. True
B. False

147Name the colour used in insulated
wired of electrical appliance.
A. Blue
B. Green
c. Brown
D. All of these
148Electromagnets are made of soft iron,
because soft iron has
A. High susceptibility and low retentivity
B. Low susceptibility and high retentivity
c. Low susceptibility and low retentivityy
D. High susceptibility and high retentivity
149What is the function of distribution box
in domestic electrical circuit
A. It distributes voltage across appliances as per need
B. It provides isolation between set of appliances and improves reliability
C. It distributes Losses among all parts of circuit equally
D. It allows user to manually distribute power as per his need
150A current carrying circular loop of radius R is placed in the ( x ) -y plane with centre at the origin. Half of the loop with ( x>0 ) is now bent so that it now lies in
the ( y-z ) plane.
A. The magnitude of magnetic moment now diminishes
B. The magnetic moment does not change.
C. The magnitude of ( bar{B} ) at ( (0,0, z), z>>R ) increases
D. The magnitude of ( bar{B} ) at ( (0,0, z), z>>R ) is unchanged.
151The frequency of A.C. (alternating current) provided to a household in USA
152State whether true or false.
In a series circuit, all appliances work independently.
A. True
B. False
153Choose the incorrect statement.
A. Alternating current is oscillatory
B. Electric power is transmitted over long distances using alternating current
C. Frequency of alternating current in India is ( 50 mathrm{Hz} )
D. Alternating current can be used for electrolysis of copper chloride.
154What will be the magnetic field at a
distance r when an electric current
flows through these things?
Wire single turn of wire Several turn of wire
An electric bulb becomes dim, when the
electric heater in parallel circuit is switched on.
Dimness decreases after sometime.
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
156One complete set of negative and positive values of alternating quantities is called
A. Time period
B. Amplitude
c. Frequency
D. cycle
157An electric bulb generally uses a filament coated with
A. Platinum
B. Thorium
c. silver
D. Radium
158The given graphs (a) and (b) represent the variation of the opposition offered by the circuit element to the flow of
alternating current, with frequency of the applied emf.ldentify the circuit
element corresponding to each graph
159An electric bulb P rated ( 220 V, 60 W ) is
working at full efficiency. Another identical bulb ( Q ) is connected across the
mains as shown in the figure. The total
power consumed is :
A . ( 20 W )
в. ( 40 W )
( c .30 W )
D. ( 70 W )
160Differentiate the following:( i=i_{0} e^{frac{-t}{R C}} )10
161A certain network consists of two ideal
and indentical voltage sources in series
and a large number of ideal resistor. The power consumed in one of the resistor is ( 4 W ) when either of the two sources is
active and other is replaced by a short circuit. The power consumed by same resistor when both sources are
simultaneously active would be:
A. 0 or ( 16 W )
B. ( 4 W ) or ( 8 W )
( mathrm{c} .0 ) or ( 8 mathrm{W} )
D. ( 8 W ) or ( 16 W )
162If a soft iron is placed inside the current carrying coil, what is the name given to the device?10
163Why are the coils of electric toasters
made of an alloy rather than a pure
164A current of 8 A flows through a 25 V car headlight bulb. Calculate the electric
power (in Watts).
165Write one merit and one de-merit of
alternating current in comparison of direct current. Obtain expression for
following in a pure inductive alternating current circuit
i) Instantaneous value of current
ii) Reactance of circuit
iii) Peak value of current Draw curve for
power in pure inductive circuit.
166Rate of dissipation of Joules heat in resistance per unit volume is (symbols have usual meaning)
A ( . sigma E )
в. ( sigma J )
( c . J E )
D. None
167In a circular current-carrying conductor if the current is flowing in anticlockwise direction, then for an observer facing the coil, the coil behaves like a
A. North pole
B. South pole
c. can be north or south pole
D. Neither north nor south pole
168The adjacent diagram shows a coil would around a soft iron bar XY. How
can the strength of the electromagnet
be increased?
A. Increasing the current in the circuit
B. Increasing the number of turns of the coil
( c . ) both ( a ) and ( b )
D. None of these
169Which of the following graph indicates
direct current?
( A )
( mathbf{c} )
( D )
170What are the characteristics of heating element used in electric heating
171The various bulbs and other electrical
appliances in a house are connected
A. In a complicated manner
B. In series
c. In parallel
D. Bulbs in series and others in parallel
172Which of the following quantities is scalar?
A. Dipole moment
B. Electric force
c. Electric field
D. Electric potential
173An electric fuse used in households
works on which principle of
A. Joule’s heating
B. Coulomb’s law
c. Maxwell’s law
D. Ohm’s law
174Fill in the blanks:
The power circuit in the house uses ampere fuse.
A. 5
B . 15
( c .50 )
D. 220
175The peak voltage of 220 Volt ( A C ) mains (in Volt) is :
A. 155.6
B. 220.0
( c .31 )
D. 440.0
176Two heater coils 1 and 2 made of the
same material are connected in parallel across the mains. The length and
diameter of the wire of coil 2 are
doubled of that coil ( 1 . ) Find the ratio of
heat generated between coil land 2
A .1: 2
B. 1: 1
c. 2: 1
D. 3: 2
177A copper voltameter is connected in
series with a coil of resistance ( 10 Omega )
When a steady current is passed through the circuit, ( 0.297 g ) of copper is found to be deposited at the cathode in 15 ( min ). The electrochemical equivalent
of copper is ( 3.3 times 10^{-7} k g C^{-} . ) Heat
liberated in the coil is:
A. ( 900 J )
в. ( 90 J )
c. ( 9 J )
D. ( 9 k J )
178Shivam went for buying a CFL from Dmart, what safety mark he should look
A. Agmark
B. ISI mark
c. Trade mark
D. Brand logo
179Which of the following equipment does not work on principle of Joule’s law?
A . Electric Heater
B. Electric Iron
c. Electric Bulb
D. Electric Fan
180In a dry cell
A. Chemical energy is converted into heat
B. Electrical energy is converted into electrical energy
C . Chemical energy is converted into electrical energy
D. Chemical energy is constant
181( ln ) an A.C. circuit in 1 second current
reduces to zero value 120 times. Hence
the frequency of A.c. current is
( mathrm{Hz} )
A . 50
в. 100
c. 60
D. 120
182The potential difference between any two points is measured in:
A. volts
B. joules
c. coulombs
D. none of these
183What is the role of switch in an electric
circuit ?
184(i) Two sets ( A ) and ( B ), of three bulbs
each, are glowing in two separate rooms.When one of the bulbs in set A is
fused, the other two bulbs also cease to glow. But in set ( mathrm{B} ), when one bulb fuses, the other two bulbs continue to glow.
explain why this phenomenon occurs.
(ii) Why do we prefer arrangements of Set B for house circuiting?
185An electric bulb is rated ‘ ( 100 W, 250 V^{prime} )
How much current will the bulb draw if
connected to a ( 250 V ) supply
A . ( 0.6 A )
в. ( 2.5 A )
( c .5 A )
D. ( 0.4 A )
186Which colour code is used for live wire?
A. Red
B. Black
c. Green
D. Yellow
187A straight conductor carrying a current is split into identical semicircular
turns of radius ( r ) as shown in the figure.
The magnetic induction at the center ( C )
of the circular loop is:
A ( cdot frac{mu_{0}}{4 r_{n}} )
в. ( frac{mu_{0} i}{8 r} )
c. ( frac{mu_{0}}{2 r} )
D. zero
188Device which works on Joule’s law of
A. Electric bulb
B. Electric heater
c. Electric iron
D. All
189In an AC circuit
A. The average value of current is zero
B. The average value of square of current is zero
C . The average power dissipation is zero
D. The rms current is ( sqrt{2} ) time of peak current
190When a current flows through a conductor its temperature
A. May increase or decrease
B. Remains same
c. Decreases
D. Increases
191The wire having a green plastic covering is a
A. live wire.
B. neutral wire
c. earth wire.
D. none of these
192Calculate the electrical energy
consumed when a current of 4.5
ampere flows through a resistance of 4 ohms for 30 minutes.
193A long straight conductor, carrying a
current ( I, ) is bent to form an almost
complete circular loop of radius ( r ) on it.
The magnetic field at the center of the
A. is directed into the paper
B. is directed out of the paper
C . has magnitude ( frac{mu_{0} I}{2 r}left(1-frac{1}{pi}right) )
D. has magnitude ( frac{mu_{0} I}{2 r}left(1+frac{1}{pi}right) )
194Using an A.C. voltmeter the potential
difference in the electrical line in a
house is read to be 234 volts. If the line
frequency is known to be 50 cycles/second, the equation for the line voltage is
A. ( V=165 sin (100 pi t) )
B. ( V=331 sin (100 pi t) )
c. ( V=220 sin (100 pi t) )
D. ( V=420 sin (100 pi t) )
195Show that the current leads the voltage by an angle ( frac{pi}{2} ) in an ac circuit containing a pure capacitor.10
196The wire having a green plastic covering is a:
A. Live wire
B. Neutral wire
c. Earth wire
D. None of these
197The frequency of alternating current in
India is
A. 50 cylces/s
B. 100 cylces/s
c. 150 cylces/s
D. 200 cylces/s
198In the absence of any current a
compass needle rests in which
direction (with respect to the Earth)?
A. South-north
B. North-south
c. East-west
D. west-east
199The potentials of two wires coming from electric poles to our houses are:
A. 440 volt and ( 220 mathrm{v} )
B. OV and 110v
c. ov and ( 220 v )
D. 300V and 500v
200Fill in the blanks with suitable words
The Sl unit of electromotive force is
201The heating element in an electric iron is made up of :
A. nichrome
B. iron
c. constantan
D. tungsten
202A metallic piece gets hot when surrounded by a coil carrying high frequency alternating current. Why
( ? )
203If the r.m.s. value of A.C. is ( l_{r m s} ) then peak
value is –
A ( cdot sqrt{2} l_{r m s} )
B ( cdot l_{r m s} / sqrt{2} )
( mathrm{c} cdot 2 sqrt{2} l_{m s} )
D ( cdot 2 l_{m s} )
204The electricity tariff in a town is ( R s .3 .00 )
per unit. Calculate the cost of running
an ( 80 W ) fan for ( 10 h ) a day for the month
of June.
A . ( R s .12 .00 )
в. ( R s .52 .00 )
c. ( R s .72 .00 )
D. Rs.92.00.
205Why are coils of electric toasters and
electric irons made of an alloy rather
that an pure metal?
206A domain in ferromagnetic iron in the
form of cube is having ( 5 times 10^{10} ) atoms.
If the side length of this domain is
1.5 ( mu m ) and each atom has a dipole moment of ( 8 times 10^{-24} mathrm{A} m^{2}, ) then
magnetisation of domain is?
A. ( 11.8 times 10^{5} mathrm{A} mathrm{m}^{-1} )
B. ( 1.18 times 10^{4} mathrm{A} mathrm{m}^{-1} )
c. ( 11.8 times 10^{4} mathrm{A} mathrm{m}^{-1} )
D. ( 1.18 times 10^{5} mathrm{A} mathrm{m}^{-1} )
207A direct current of ( 5 A ) is superimposed
on an alternating current ( boldsymbol{I}=mathbf{1 0} sin boldsymbol{omega} boldsymbol{t} )
flowing through a wire. The effective value of the resulting current will be
( mathbf{A} cdot(15 / 2) A )
B. ( 5 sqrt{3} A )
c. ( 5 sqrt{5} ) A
D. 15 A
208Complete the given statement. The
voltage across each light bulb in a
parallel circuit:
A. is equal to the voltage of the battery
B. is determined by the resistance of the bulb
C. is determined by the current flowing through the bulb
D. is equal to the sum of the voltages lost in each bulb
E. is equal to the total current divided by the resistance of the bulb
209Name the effect of current responsible for the glow of the bulb in an electric circuit.
A. Chemical
B. Heating
c. Magnetic
210An electric heater which is connected to
a ( 220 mathrm{V} ) supply line has two resistance
coils. ( A ) and ( B ) of ( 24 Omega ) resistance each.
these coils can be used separately (one at a time), in series or in parallel.
calculate the current drawn when:
Only one coil A is used
coils ( A ) and ( B ) are used in series
211A heater at ( 220 V ) boils a volume of
water in 5 minutes time. If the heater is
operated at ( 110 V ), the same volume of
water will boil in ( 10 n ) minutes. Find the
value of ( n ? )
212Name the colour code of the wire which
is connected to the metallic body of an
213Find the resistance of ( 1000 mathrm{W}-250 mathrm{V} )
heater wire.
214Which is not a correct advantage of parallel combination in domestic
A. Same voltage of the mains is available for all electrical appliances.
B. Switching on or off of one switch has no effect on the other
C. If one appliance stops working, other appliances keep on working
D. none
215The diagram represents a magnetic
field. What causes this field?
( A . ) A bar magnet
B. A solenoid carrying a current
C. A straight wire carrying a current
D. Two north poles close together
216Why are multiple fuses used in
domestic electric circuit
A. It reduces the average cost
B. It increases efficiency of system
C. It guarantees system will always work perfectly
D. Failure of one of the fuses allow system to continue working in applications where fault has not ocured
217The Magnetic effect of current was discovered by:
A. John Ambrose Fleming
B. Hans Christian Oersted
c. Michael Faraday
D. André-Marie Ampère
218What happens to the reading of
( A_{1}, A_{2}, A_{3} ) and ( A ) when the bulb ( B_{2} ) gets
A ( . A_{1}=1 A, A_{2}=0 A, A_{3}=0 A ) and ( A=2 A )
B. ( A_{1}=1 A, A_{2}=0 A, A_{3}=1 A ) and ( A=2 A )
C. ( A_{1}=2 A, A_{2}=0 A, A_{3}=1 A ) and ( A=2 A )
D. ( A_{1}=1 A, A_{2}=0 A, A_{3}=1 A ) and ( A=1 A )
219Each electrical appliance is provided
with a
Fill in the blank.
( A cdot 3 )
B. 2
( c )
D. 4
220For making an electromagnet the best material to be used is
A. stainless steel
B. silver
c. soft iron
D. nickel
221What do you understand by the thermal
effect of electric current?
222Which of the following entities are closely associated to each other
A. Gravitation and nuclear fusion
B. Electricity and magnetism
c. Chemical Bonding and Planetary motion
D. None
223Which of the following phenomenon can
be related to electric current
A. Magentism
B. Gravitation
c. Nuclear Fission
D. chemical Bonding
224The rating of a fuse depends upon the
A. thickness of the fuse wire
B. length of the wire
( c cdot ) both
D. none
225When does overloading occur?
A. When live wire and neutral wire come into direct
B. When live wire and neutral wire come into indirect
C. When two live wires come into direct contact.
D. When two neutral wire come into direct contact.
226Derive an expression for the energy seated in a capacitor. In what form is
the energy stored in a charged capacitor?
227How the small bulbs, which are used for
decoration purpose,are connected?
A. in parallel
B. in series
c. in mixed order
D. all of the above
228Create a concept map using the following words.

Electromagnetism, Electricity, Magnetism, Solenoid, Electromagnet, Magnet field, Electromagnetic induction, Generators, and
Transformers, motors.

229An electric heater kept in vacuum is
heated continuously by passing electric
current. Its temperature:
A. will go on rising with time
B. will stop after sometime as it will loose heat to the surroundings by conduction
C. will rise for sometime and thereafter will starts falling
D. will become constant after sometime because of loss of heat due to radiation
230An ac voltmeter reads ( 220 mathrm{V} ). If the line
frequency is ( 50 H z, ) then the equation
for the line voltage is
A. ( V=220 sin 50 t )
B. ( V=220 sin 100 t )
c. ( V=311 sin 50 pi t )
D. ( V=311 sin 100 pi t )
231From below which are the applications of heating effect of electric current?
A. Electric immersion water heater
B. Electric Iron Box
c. Electric Fuse
D. All of the above
232The frequency of A.C mains in India is
( mathbf{A} cdot 30 H z )
B. ( 50 H z )
( mathbf{c} cdot 60 H z )
D. ( 120 H z )
233Horse shoe magnet is
A. v shaped
B. P shaped
c. u shaped
D. All
234The colour code of a resistor is brown, black and brown. Then the value of
resistance is
A. ( 10 Omega )
в. 100 тл
c. ( 0.1 k Omega )
D. 1000 ( Omega )
235If the length of the filament of a heater
is reduced by ( 10 % ), the power of the heater will
A. increase by about 9%
B. increase by about 11%
c. increase by about ( 19 % )
D. decrease by about ( 10 % )
Sensitive electrical instruments should
not be placed in the vicinity of an electromagnet.
Electromagnet can damage the instruments.
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
237The quantity ( boldsymbol{X}=frac{boldsymbol{epsilon}_{0} boldsymbol{L} boldsymbol{V}}{boldsymbol{t}}: boldsymbol{epsilon}_{0} ) is the
permittivity of free space, ( boldsymbol{L} ) is length, ( boldsymbol{V} )
is potential difference and ( t ) is time. The
dimensions of ( X ) are same as that of
A . Resistance
B. Charge
c. voltage
D. current
238An electric meter reads 8950 KWh at
the end of the month,while at the
beginning of the month the reading was
( 8833 mathrm{KWh} ). How many units of electricity are consumed? If one unit
( operatorname{costs} ) Rs. ( 4.30, ) find the cost of the
electrical energy consumed
239An alternating voltage is represented as ( E=20 sin 300 t . ) The average value of
voltage over one cycle will be?
A. zero
B. 10 volt
c. ( 20 sqrt{2} ) volt
D. ( frac{20}{sqrt{2}} ) volt
240A.C power is transmitted from a power
house at a high voltage as
A. the rate of transmission is faster at high voltages
B. it is more economical due to less power loss
C. power cannot be transmitted at low voltages
D. a precaution against theft of transmission lines
241Fill the blank.
Voltmeter is always connected in ( ldots ) with the device.
A. series
B. parallel
c. series and parallel both
D. the cell
242( ln operatorname{an} A C ) generator, a coil with ( N ) turns, all of the same area ( A ) and total
resistance ( boldsymbol{R} ), rotates with frequency ( boldsymbol{omega} )
in a magnetic field ( B ). The
maximum value of e.m.f. generated in the coil is :
A. NABR ( omega )
243A circular loop of radius R carries a current I. Obtain an expression for the magnetic field at a point on its axis at a distance ( x ) from its centre10
244A secondary cell can provide
A . Low
B. Highh
c. Both
D. None
245A house has four tubelights, three fans and a television. Each tubelight draws
( 40 W . ) The fan draws ( 80 W ) and the
television draws ( 100 mathrm{W} ). On an average,
all the tubelights are kept on for 5 hours, all fans for 12 hours and the
television for 6 hours everyday. Find the
( operatorname{cost} ) of electric energy used in 30 days at the rate of ( R s .3 .00 ) per KWH
246Write two properties of magnetic field
247Generation of Alternating Current in India is done at
( A cdot 45 ) Н
в. 50 нz
c. 60 Н
D. 55 Hz
248The reading of the voltmeter connected
across ( 20 Omega ) resistance is
( A cdot 15 V )
В. ( 10 V )
( c .5 V )
D. ( 22.5 V )
249n the circuit shown, what is the
potential difference ( V_{P Q} ? )
( A cdot+3 V )
B. ( +2 v )
c. ( -2 v )
D. None of thes
250An alternating current in circuit is
( operatorname{given} ) by ( I=20 sin (100 pi t+0.005 pi) A )
The r.m.s value and the frequency of current respectively are:
A . ( 10 A ) and ( 100 H z )
B. ( 10 A ) and ( 50 mathrm{Hz} )
c. ( 10 sqrt{2} ) A and ( 50 mathrm{Hz} )
D. ( 10 sqrt{2} ) A and ( 100 mathrm{Hz} )
251Why are alloys commonly used in electrical heating devices?
A. Due to high resistivity
B. Due to low resistivity
c. Due to high elasticity
D. Due to medium resistivity
252In the network shown, the sources of
emf ( 2 vee, 12 ) V and 16 V are taken to be
ideal. Select incorrect statements from
the following:
This question has multiple correct options
A ( cdot ) The potential drop across ( 4 Omega ) is ( frac{28}{13} vee )
B. The current through 2 v battery is ( frac{17}{13} ) A, discharging.
C ‘ the current through 2 V battery is ( frac{17}{13} ) A, charging.
D. The potential drop across ( 8 Omega ) is ( frac{60}{13} vee )
253What will be the frequency of an alternating current, if its direction changes after every 0.05 s?
A. ( 5 mathrm{Hz} )
в. 10нz
( c cdot 50 H z )
D. онz
254The work that has to be done in
transferring unit positive charge from one point to the other is called
A. electric potential energy
B. electrical potential
c. electric potential difference
D. electric field
255The north-south polarities of an electromagnet can be determined with the help of
A. Maxwell’s corkscrew rule
B. right hand thumb rule
c. clock face rule
D. Fleming’s left-hand rule
256Which of the following is FALSE ?
A. some of the energy produced by the light bulb takes the form of heat
B. the battery is the source of the electrons flowing around the circuit
C. the current entering the light bulb equals the current leaving the light bulb
D. the potential in the wire to the left of the light bulb differs from the potential in the wire to the right of the bulb
257In our houses, we receive AC current at
a voltage of with a
frequency of
258In which circuit can the lamps be
switched on and off independently?
( A )
( c )
( D )
259An ( A C ) source is rated ( 220 V, 50 H z )
The average voltage, is calculated in a time interval of 0.01 s. It
A. must be zero
B. may be zero
( c . ) is never zero
D. is ( (220 / sqrt{2}) V )
260What happens on connecting too many appliances at a time to a single socket?10
261If the instantaneous emf and the
instantaneous current equations of an
A.C. circuit are respectively
( e=E_{0} sin (omega t-pi / 6), i=I_{0} sin (omega t+ )
( boldsymbol{pi} / boldsymbol{6}), ) then the phase difference
between voltage and current is :
A ( cdot frac{pi}{3} )
B. zero
( c cdot frac{pi}{2} )
262A temporary magnet is made of
A. cast iron
B. steel
C. soft iron
D. stainless steel
263All domestic electrical circuits are
A. In series
B. In parallel
c. Both
D. None of these
264Two capacitors of caacity ( C_{1} ) and ( C_{2} ) are connected in series and potential difference V is applied across it. Then
the potential difference across ( C_{1} ) will
( ^{mathrm{A}} cdot frac{C_{2} V}{C_{1}+C_{2}} )
в. ( frac{C_{1} V}{C_{1}+C_{2}} )
( ^{c} cdotleft(1+frac{C_{2}}{C_{1}}right) V )
D. ( left(1-frac{C_{2}}{C_{1}}right) v )
265Two electric wires coming out of the
meter are connected to the
A. electric equipment
B. switch of the bulbs
c. main switch
D. switch of the electric equipments
266What two precautions should be taken
to avoid the overloading of domestic
electric circuits?
267Every electric appliance is marked with This question has multiple correct options
A. power
B. potential difference
c. charge
D. resistance
268Match the columns
& A & B \
a. & green plastic covering & 1. & live wire \
hline b. & black plastic covering & 2. & neutral wire \
c. & red plastic covering & 3. & earth wire
A. a-2, b-3, c-1
B. ( a-1, b-2, c-3 )
c. ( a-3, b-1, c-2 )
D. ( a-3, b-2, c-1 )
269In domestic electric circuit,appliances are connected in parallel. Why?
A. because it consumes less power
B. because if one appliance stops working,other appliances keep on working
c. because it is longer than series supply so can be distributed to the whole house
D. it is comparatively easier to create.
270The relationship between A.C voltage and time in Sl unit is ( V= )
( 120 sin (100 pi T) cos (100 pi t) ) volt value
of peak voltage and frequency will be :
A. 120 volt and 100 ( mathrm{Hz} )
B . ( frac{120}{sqrt{2}} ) volt and ( 100 mathrm{Hz} )
c. 60 volt and 200 Hz
D. 60 volt and 100 нz
271A long, straight wire of radius a carries a current distributed uniformlt over its
cross-section. The ratio of the magnetic fields due to the wire at distance ( frac{a}{3} ) and
( 2 a, ) respectively from the axis of the
wire is?
A ( cdot 2 / 3 )
B. ( 3 / 2 )
c. ( 1 / 2 )
D. 2
272in figure carrying current ( boldsymbol{I} . boldsymbol{A} boldsymbol{B} ) and ( boldsymbol{B} boldsymbol{C} )
parts are straight, long, and at right
angle. At ( D ) wire forms a circular turn
DM ( N D ) of radius ( R . A B, B C ) parts are
tangential to circular turn at ( N ) and ( D )
The magnetic field at the centre of
circle is
A ( cdot frac{mu_{0} I}{2 pi R}left(pi-frac{1}{sqrt{2}}right) )
B. ( frac{mu_{0} I}{2 R} )
c. ( frac{mu_{0} I}{2 pi R}left(pi+frac{1}{sqrt{2}}right) )
( ^{mathrm{D}} cdot frac{mu_{0} I}{2 pi R}(pi+1) )
273What are the characteristic properties of fuse wire?10
274Whenever an electric current is passed through a conductor,it gets heated up.this means that a part of electrical energy, given to the conductor, gets converted to
A. potential energy
B. gravitational energy
c. heat energy
D. none of these
275A current ( I ) is flowing in a straight
conductor wire of length ( L ). The magnetic induction at a point perpendicular distance ( frac{L}{4} ) from its centre will be:
A ( cdot frac{4 mu_{0} i}{sqrt{5} pi L} )
в. ( frac{mu_{0} i}{2 pi L} )
c. ( frac{mu_{0} i}{sqrt{2} L} )
D. zero

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