# Kinetic Theory Questions

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

#### List of kinetic theory Questions

Question NoQuestionsClass
1The average kinetic energy of the
molecules of an ideal gas at ( 10^{circ} mathrm{C} ) has the value E. The temperature at which the kinetic energy of the same gas becomes ( 2 mathrm{E} ) is
( mathbf{A} cdot 5^{circ} C )
В ( cdot 10^{circ} mathrm{C} )
( c cdot 40^{circ} C )
D. None of these
11
2If ( triangle E ) is the heat of reaction for
( C_{2} H_{3} O H_{(1)}+3 O_{2(g)} rightarrow 2 C O_{2(s)}+ )
( mathbf{3} boldsymbol{H}_{2} mathbf{0}_{(1)} ) at constant volume, the ( triangle boldsymbol{H} )
Heat of reaction at constant pressure) at constant temperature is:
A ( . triangle H=triangle E+2 R T )
B. ( triangle H=triangle E-2 R T )
c. ( triangle H=Delta E+R T )
D. ( triangle H=triangle E-R T )
11
3How many degrees of freedom are
associated with 2grams of He at NTP?
A. 3
B. ( 3.01 times 10^{23} )
c. ( 9.03 times 10^{23} )
D. 6
11
4The mass of a gas molecules is ( 4 times 10^{-30} mathrm{kg} )
If ( 10^{23} ) molecules strike per second at ( 4 mathrm{m}^{2} )
area with a velocity ( 10^{7} mathrm{m} / mathrm{s} ), then the
pressure exerted on the surface will be
A. 1 Pascal
B. 3 Pascal
c. 2 Pascal
D. 4 Pascal
11
5A monoatomic ideal gas ( left(C_{V}=frac{3}{2} Rright) ) is
allowed to expand adiabatically and reversibly from initial volume of ( 8 mathrm{L} ) at
( 300 mathrm{K} ) to a volume of ( V_{2} ) at ( 250 mathrm{K} . V_{2} ) is:
(Given ( left.(4.8)^{1 / 2}=2.2right) )
A . ( 10.5 mathrm{L} )
B. 23 L
( c .8 .5 )
D. 50.5
11
6Assertion
STATEMENT-1
The total translational kinetic energy of all the molecules of a given mass of an ideal gas is 1.5 times the product of its pressure and its volume
Reason
STATEMENT-2
The molecules of a gas collide with each
other and the velocities of the
molecules change due to the collision.
A. Statement-1 is True, Statement-2 is True; Statement- is a correct explanation for Statement- –
B. Statement- – is True, Statement-2 is True; Statement-2 is NOT a correct explanation for Statement-
c. Statement- – 1 is True, Statement- 2 is False
D. Statement- – is False, Statement-2 is True
11
7A quantity of 10 g of a gas at 1 atm pressure is cooled from ( 273^{circ} mathrm{C} ) to ( 273 mathrm{K} )
keeping its volume constant, the final
pressure of the gas will be?
A. 273 atm
B. 0.5 atm
c. 0.2 atm
D. 0.1 atm
11
8The pressure coefficient of a gas is ( operatorname{(in} /^{0} C )
):
A. 0.00367
в. – -27
( c . ) 98
D. 3.14
11
9The quantity ( frac{2 U}{f k T} ) represents (where ( U= ) internal energy of gas
A. mass of the gas
B. kinetic energy of the gas
c. number of moles of the gas
D. number of molecules in the gas
11
10A container is filled with 20 moles of an
ideal diatomic gas at absolute
temperature ( T . ) When heat is supplied
to gas, temperature remains constant but 8 moles dissociate into atoms. Heat
energy given to gas is
A ( .4 R T )
в. ( 6 R T )
( c .3 R T )
D. ( 5 R T )
11
11The total kinetic energy of 1 mole of ( N_{2} ) at ( 27 mathrm{C} ) will be approximately
A . 3739.662
B. 1500 calorie
c. 1500 kilo calorie
D. 1500 erg.
11
12The graph drawn between presure and
volume in boyles law experiment is
shown in figure, then:
A ( cdot T_{1}>T_{2} )
в. ( T_{2}>T_{1} )
( c cdot T_{1}=T_{2} )
D. ( frac{T_{1}}{T_{2}}=C )
11
13If at the same temperature and pressure, the densities of two diatomic
gases are ( d_{1} ) and ( d_{2} ) respectively, the
ratio of mean kinetic energy per
molecule of gases will be :
A . 1: 1
B . ( d_{1}: d_{2} )
D. ( sqrt{d_{2}}: sqrt{d_{1}} )
11
14A molecule of gas in a container hits one wall (1) normally and rebounds back. It suffers no collision and hits the
opposite wall (2) which is at an angle of
( 30^{circ} ) with wall 1
Assuming the collisions to be elastic
and the small collision time to be the
same for both the walls, the magnitude
of average force by wall 2. ( left(F_{2}right) ) provided the molecule during collision satisfy
( mathbf{A} cdot F_{1}>F_{2} )
B. ( F_{1}<F_{2} )
C ( cdot F_{1}=F_{2}, ) both non-zero
D. ( F_{1}=F_{2}=0 )
11
15A sample of gas in a box is at pressure
( P_{0} ) and temperature ( T_{0} . ) If number of
molecules is doubled and total kinetic
energy of the gas kept constant then final temperature and pressure will be
( mathbf{A} cdot T_{0} cdot P_{0} )
в. ( T_{0} .2 P_{0} )
c. ( frac{T_{0}}{2} .2 P_{0} )
D. ( frac{T_{0}}{2} cdot P_{0} )
11
16A cylinder of capacity ( 20 L ) is filled with
( boldsymbol{H}_{2} ) gas. The total average kinetic energy
of translatory motion of its molecules is
( 1.5 times 10^{5} J . ) The pressure of hydrogen in
the cylinder is
A ( .2 times 10^{6} mathrm{N} / mathrm{m}^{2} )
в. ( 3 times 10^{6} mathrm{N} / mathrm{m}^{2} )
c. ( 4 times 10^{6} N / m^{2} )
D. ( 5 times 10^{6} N / m^{2} )
11
17The number of vibrational degrees of
freedom for a ( C O_{2} ) molecule is
( A cdot 4 )
B. 5
( c cdot 6 )
D.
11
18The average kinetic energy of thermal
neutron is of the order of :
(Boltzmann’s constant ( k_{B}=8 times )
( left.10^{-5} e V / Kright) )
A . ( 0.03 e V )
в. ( 3 e V )
c. ( 3 k e V )
D. 3MeV
11
19Three closed vessels ( A, B ) and ( C ) are at the
same temperature T and contain gases which obey Maxwell distribution law of
velocities. Vessel A contains ( O_{2}, ) B only ( N_{2} )
and ( mathrm{C} ) mixture of equal quantities of ( mathrm{O}_{2} )
and ( N_{2} ). If the average speed of ( O_{2} )
molecules in vessel ( mathrm{A} ) is ( V_{1} ) and that of ( N_{1} )
molecules in vessel B is ( V_{2} ), then the
average speed of the ( O_{2} ) molecules in
vessel C is
A ( cdot frac{left(v_{1}+v_{2}right)}{2} )
B. ( V_{1} )
c. ( sqrt{v_{1} v_{2}} )
D. None of these
11
20A light container having a diatomic gas enclosed with in is moving with velocity
v. Mass of the gas is ( M ) and number of
moles is ( n )
What is the kinetic energy of gas with respect to centre of mass of the system? What is the kinetic energy of gas with respect to ground?
11
21When an air bubble of radius r rises from
the bottom to the surface of a lake, its radius becomes ( 5 r / 4( ) the pressure of
the atmosphere is equal to the ( 10 mathrm{m} ) height of water column).ff the temperature is constant and the surface tension is neglected, the depth of the lake is
A . 3.53m
B. 6.53m
c. ( 9.53 mathrm{m} )
D. 12.53m
11
22In physics, the mean free path is the average distance traveled by a moving particle (such as an atom, a molecule, a photon) between successive impacts (collisions), which modify its direction or energy or other particle properties. In which of the following mean free path is used ?
A. to estimate the resistivity of a material
B. to design a chemical apparatus
c. It can be used in optics and in acoustics
D. All of the above
11
23An inverted vessel (bell) lying at the bottom of a lake, ( 50.6 mathrm{m} ) deep has ( 50 mathrm{cc} ) of air trapped in it. The bell is brought to
the surface of lake. The volume of the
trapped air will now be
A . 200 ç
B. 250 cc
c. 300 cc
D. 350 cc
11
24STATEMENT-1: According to kinetic
theory of gases the internal energy of a given sample of an ideal gas is only kinetic.
STATEMENT-2: The ideal gas molecules
exert force on each other only when they
collide.
A. STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is a correct explanation for STATEMENT-
1
B. STATEMENT-1 is True, STATEMENT-2 is True; STATEMENT-2 is NOT a correct explanation for STATEMENT-1
C. STATEMENT-1 is True, STATEMENT-2 is False
D. STATEMENT-1 is False, STATEMENT-2 is True
11
25Consider a classroom of dimensions
( (5 times 10 times 3) m^{3} ) at temperature ( 20^{circ} C )
and pressure 1 atm. There are 50 people in the room, each losing energy at the average of 150 watts. Assuming that the walls, ceiling, floor, and furniture are perfectly insulated and none of them is absorbing heat. How much time will be needed for raising the temperature of air in the room to the
body temperature ( left(37^{circ} Cright) ?left[text { For air } C_{p}=right. ) ( frac{7}{2} R ) and neglect the loss of air to the outside as the temperature rises
A .422 sec
в. ( 411.3 mathrm{sec} )
c. ( 421.1 mathrm{sec} )
D. ( 413.1 mathrm{sec} )
11
26An ideal gas is heated in a container that has a fixed volume. Identify which of the following will increase as a result of this heating?
I. The pressure against the walls of the container
Il. The average kinetic energy of the gas
molecules
III. The number of moles of gas in the
container
A. I only
B. I and II only
c. II and III only
D. II only
E . III only
11
27Assertion
The total translational kinetic energy of
all the molecules of a given mass of an ideal gas is 1.5 times the product of its
pressure and its volume.
Reason
The molecules of a gas collide with each other and the velocities of the
molecules change due to the collision.
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 and Reason is correct
11
28In rising from the bottom of a lake to the top, the temperature of air bubble remains unchanged, but the diameter gets doubled. If ( h ) is the barometric
height (expressed in metres of mercury
of relative density ( rho ) ) at surface of the lake, the depth of the lake (in metres) is
( mathbf{A} cdot 8 rho h )
B. ( 4 rho h )
( c cdot 7 rho h )
D. ( 2 rho h )
11
29If ( bar{v}, v_{r m s} ) and ( v_{p} ) represent the mean
speed, root mean square and most probable speed of the molecules in an ideal monoatomic gas at temperature
( T ) and if ( m ) is mass of the molecule,
then
A ( cdot v_{p}<bar{v}<v_{r m} )
B. No molecule can have a speed greater than ( sqrt{2 v_{r m s}} )
C. No molecule can have a speed less than ( v_{p} / sqrt{2} )
D. None of the above
11
30A gas has an average speed of ( 10 m / s )
and an average time of ( 0.1 s ) between collisions.What is its mean free path?
A. ( 1 m )
в. ( 0.1 m )
( c .2 m )
D. None of the above
11
31The gases carbon-monoxide ( (C O) ) and nitrogen at the same temperature have
kinetic energies ( boldsymbol{E}_{1} ) and ( boldsymbol{E}_{2} ) respectively Then
A. ( E_{1}=E_{2} )
в. ( E_{1}>E_{2} )
c. ( E_{1}<E_{2} )
D. ( E_{1} ) and ( E_{2} ) cannot be compared
11
32A gas mixture contain ( 1 g H_{2} ) and ( 1 g H_{e} ) temperature of gas mixture is
increased from ( 0^{circ} ) to ( 100^{circ} C ) at isobaric
process. Then find given heat of gas mixture
( left[gamma_{H e}=mathbf{5} / 3, gamma_{H e}=mathbf{7} / mathbf{5}, R=2 c a l / m o lright. )
A . 124 call
в. 327 cal
c. 218 cal
D. 475 cal
11
33Estimate the mean free path and
collision frequency of a nitrogen molecule in a cylinder containing nitrogen at 2.0 atm and temperature 17
( ^{o} C . ) take the radius of a nitrogen
molecule to be roughly 1.0 A. Compare the collision time with the time the
molecule moves freely between two successive collisions (Molecular mass
of ( mathrm{N}_{2}=28.0 mathrm{u} )
11
34The average kinetic energy of hydrogen molecule at NTP will be
A. ( 0.4 times 10^{-20} ) Joule /molecule
B . ( 1.56 times 10^{-20} ) Joule / molecule
c. zero
D. ( 5.6 times 10^{-20} ) Joule /molecule
11
35The number of gas molecules striking per second per square meter of the top surface of a table placed in a room at
( 20^{circ} mathrm{C} ) and 1 atmospheric pressure is of
the order of ( left(k_{B}=1.4 times 10^{-23} J / K, ) and right.
the average mass of an air molecule is
( left.mathbf{5} times mathbf{1 0}^{-mathbf{2 7}} mathbf{k g}right) )
( A cdot 10^{27} )
B. ( 10^{23} )
( c cdot 10^{25} )
D. ( 10^{2} )
11
36The ( H ) calories of heat is required to
increase the temperature of one mole of
monoatomic gas from ( 20^{circ} mathrm{C} ) to ( 30^{circ} mathrm{C} ) at
constant volume. The quantity of heat required to increase the temperature
of 2 moles of a diatomic gas from ( 20^{circ} mathrm{C} )
to ( 25^{circ} C ) is at constant volume is :
A ( cdot frac{4 H}{3} )
в. ( frac{5 H}{3} )
c. ( 2 H )
D. ( frac{7 H}{3} )
11
37Identify the type of gas filled in
container ( A ) and ( B ) respectively
A. Mono, mono
B. Dia, dia
C. Mono, dia
D. Dia, Mono
11
38State whether true or false:
Mean free path order for some gases at
( 273 mathrm{K} ) and 1 atm ( mathrm{P} ) is
( boldsymbol{H} boldsymbol{e}>boldsymbol{H}_{2}>boldsymbol{O}_{2}>boldsymbol{N}_{2}>boldsymbol{C} boldsymbol{O}_{2} )
A. True
B. False
11
39At what temperature will the mean molecular energy of a perfect gas be one-third of its value of ( 27^{circ} mathrm{C} ? )
A ( cdot 10^{circ} mathrm{C} )
В . ( 10^{1} mathrm{K} )
( c cdot 10^{2} k )
D. ( 10^{3} ) J
11
40A 100 feet long classroom maintains
seating row after every 10 feet and has doors on both front and back sides. A
laughing gas ( left(N_{2} Oright) ) cylinder and a tear gas (methane) cylinder were opened simultaneously at the front and the back door respectively. Assuming both the gases were present at the same temperature and pressure and the cylinder has similar valve dimensions. If the student of ( n^{t h} ) row, from the front,
simultaneously weeps and laughs, the value of ( n ) is
A. 5
B. 4
( c cdot 6 )
D.
11
41A certain mass of an ideal gas
undergoes a reversible isothermal compression. Its molecules, compared
with the initial state, will then have the
same
(i) root mean square velocity
(ii) mean momentum
(iii) mean kinetic energy
( A cdot(i),(text { ii) },( text { iii) } )
B. (i), (ii)
c. (ii), (iii)
D. (i)
11
42Absolute zero (OK) is that temperature
at which
A. Matter ceases to exit
B. Ice melts and water freezes
c. volume and pressure of a gas become zero
D. None of the above
11
43Two gases, carbon monoxide ( (C O) ) and
nitrogen ( left(N_{2}right) ) at the same temperature
have kinetic energies ( boldsymbol{E}_{1} ) and ( boldsymbol{E}_{2} )
respectively. Then
A ( . E_{1}=E_{2} )
в. ( E_{1}>E_{2} )
( mathbf{c} cdot E_{1}<E_{2} )
D. ( E_{1} ) and ( E_{2} ) cannot be compared
11
44A cylinder contains helium at 2.5
atmosphere pressure. Another identical cylinder contains argon at 1.5
atmosphere pressure at the same temperature. If both the gases are filled
in any one of the cylinders, the pressure of the mixture will be:
A. 1.5 atm
B. 2.5 atm
( c cdot 4 a t m )
D. none of these
11
45Calculate the average molecular kinetic
energy :
(a) per kilomole,
(b) per kilogram,
of oxygen at ( 27^{circ} mathrm{C} )
( (R=8320 J / K m o l e K, ) Avogadro’s
number ( =mathbf{6 . 0 3} times )
( 10^{26} ) molecules ( / ) Kmole
11
46One ( k g ) of a diatomic gas is at a
pressure of ( 8 times 10^{4} mathrm{N} / mathrm{m}^{2} . ) The density
of the ( operatorname{gas} ) is ( 4 mathrm{kg} / mathrm{m}^{3} . ) What is the energy of the gas due to its thermal
motion?
A. ( 3 times 10^{4} mathrm{J} )
B . ( 5 times 10^{4} mathrm{J} )
c ( cdot 6 times 10^{4} mathrm{J} )
D. ( 7 times 10^{4} mathrm{J} )
11
47Assertion
Mean free path of a gas molecules varies inversely as density of the gas.
Reason
Mean free path varies inversely as
pressure of the gas.
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
11
48The mean free path of a gas varies with
absolute temperature as:
A. ( T )
B. ( T^{-1} )
( c cdot T^{2} )
( mathbf{D} cdot mathbf{T}^{4} )
11
49The quantity of heat required to heat 1 mole of a monoatomic gas through one degree ( K ) at constant pressure is:
A . 3.5
B. 2.5 R
( c cdot 1.5 R )
D. none of these
11
50Two kg of a monoatomic gas is at a pressure of ( 4 times 10^{4} N / m^{2} . ) The density
of the gas is ( 8 k g / m^{3} . ) What is the order
of energy of the gas due to its thermal motion?
A ( cdot 10^{3} J )
( J )
В. ( 10^{5} J )
( c cdot 10^{6} J )
D. ( 10^{4} J )
11
51A monoatomic ideal gas undergoes a process in which the ratio of ( boldsymbol{P} ) to ( boldsymbol{V} ) at
any instant is constant and equal to unity. The molar heat capacity of gas is:
( mathbf{A} cdot 1.5 R )
B. ( 2.0 R )
c. ( 2.5 R )
D. 0
11
52Match following11
53Three containers of the same volume
contain three gases. The masses of their
molecules being ( mathrm{m}_{1}, mathrm{m}_{2} ) and ( mathrm{m}_{3} ) and
number of molecules in these containers
is ( mathrm{N}_{1}, mathrm{N}_{2} ) and ( mathrm{N}_{3} ). The pressure in
the containers are ( mathrm{P}_{1}, mathrm{P}_{2} ) and ( mathrm{P}_{3} )
respectively. All the gases are now mixed up and put in these containers. The
pressure ( mathrm{P} ) of the mixture is
( mathbf{A} cdot Pleft(P_{1}+P_{2}+P_{3}right) )
11
542kg of lce block should be dropped from “x km’ height to melt completely. The 8 kg of ice block should be dropped from height
( A cdot 4 x k m )
B. ( times mathrm{km} )
c. ( 2 times mathrm{km} )
D. 3x
11
55The number of molecules in ( 22.4 mathrm{cm}^{3} ) of
nitrogen gas at STP is
A ( .6 .023 times 10^{20} )
В. ( 6.023 times 10^{23} )
c. ( 22.4 times 10^{20} )
D. ( 22.4 times 10^{23} )
11
56If the mean free-path of gaseous
molecule is ( 60 mathrm{cm} ) at a pressure of ( 1 times )
( 10^{-4} mathrm{mm} ) mercury, what will be its
mean free-path when the pressure is
increased to ( 1 times 10^{-2} mathrm{mm} ) mercury?
A ( cdot 6.0 times 10^{-1} mathrm{cm} )
B. ( 6.0 mathrm{cm} )
( mathbf{c} cdot 6.0 times 10^{-2} mathrm{cm} )
D. ( 6.0 times 10^{3} mathrm{cm} )
11
57A vessel containing 9 litres of an ideal gas at ( 760 mathrm{mm} ) pressure is connected to an evacuated 9 litre vessel. The resultant
pressure is
( A cdot 380 mathrm{mm} )
B. 760 mm
c. ( 190 mathrm{mm} )
D. 1140 mm
11
58An insulated box containing monatomic ideal gas of molar mass ( mathrm{M} )
is moving with a uniform speed v. The box suddenly stops and consequently the gas acquires a new temperature. Calculate the change in the
temperature of the gas. Neglect heat absorbed by the box.
A ( cdot Delta T=2 frac{M v^{2}}{3 R} )
в. ( Delta T=frac{M v^{2}}{3 R} )
( ^{mathbf{C}} Delta T=3 frac{M v^{2}}{3 R} )
D. ( quad Delta T=4 frac{M v^{2}}{3 R} )
11
59The maximum speed of the molecules of a gas in a vessel is ( 400 mathrm{m} / mathrm{s} ). If half of the gas leaks out, at constant
temperature, the ( r m s ) speed of the
remaining molecules will be-
A. ( 800 mathrm{m} / mathrm{s} )
B . ( 400 sqrt{2} mathrm{m} / mathrm{s} )
c. ( 400 mathrm{m} / mathrm{s} )
D. ( 200 mathrm{m} / mathrm{s} )
11
60A certain mass of hydrogen gas is introduced into a vessel at room
temperature, the final pressure of the gas
in the vessel is
( A cdot 85 mathrm{cm} ) of ( mathrm{Hg} )
B. 78 cm of Hg
( c cdot 63 mathrm{cm} ) of ( mathrm{Hg} )
D. ( 58 mathrm{cm} ) of ( mathrm{Hg} )
11
61Two blocks of the same metal having
the same mass and at temperature ( T_{1} )
and ( T_{2}, ) respectively. are brought in
contact with each other and allowed to
attain thermal equilibrium at constant
pressure. The change in entropy, ( Delta S ), for this process is :
( ^{mathbf{A}} cdot 2 C_{p} ln left(frac{T_{1}+T_{2}}{4 T_{1} T_{2}}right) )
( ^{mathrm{B}} 2 C_{p} ln left[frac{left(T_{1}+T_{2}right)^{frac{1}{2}}}{T_{1} T_{2}}right] )
( ^{mathbf{c}} cdot_{C_{p} l n}left[frac{left(T_{1}+T_{2}right)^{2}}{4 T_{1} T_{2}}right] )
D ( cdot 2 C_{p} ln left[frac{T_{1}+T_{2}}{2 T_{1} T_{2}}right] )
11
62Density is least in
A. Sold
B. Liquid
c. Both A and B
D. Gas
11
63Modern vacuum pumps can evacuate a
vessel down to a pressure of ( 4.0 times ) ( 10^{-15} ) atm. At room temperature
( (300 K), ) taking ( R= )
( mathbf{8 . 3 J K}^{-1} quad boldsymbol{m o l e}^{-1}, mathbf{1} quad boldsymbol{a t m}= )
( mathbf{1 0}^{5} boldsymbol{P a} quad ) and ( boldsymbol{N}_{text {Avagadro }}=mathbf{6} times )
( 10^{23} ) mole ( ^{-1} ), the mean distance
between the molecules of gas in an evacuated vessel will be of the order of :
( mathbf{A} cdot 0.2 mu m )
B. ( 0.3 mu ) m
( c .0 .2 mathrm{mm} )
D. ( 0.2 n m )
11
64The temperature of a gas is due to
A. P.E. of its molecules
B. K.E. of its molecules
C. Attractive forces between molecules
D. Repulsive forces between molecules
11
65( Delta C_{p} ) for change ( N_{2}(g)+3 H_{2}(g)= )
( mathbf{2} N boldsymbol{H}_{3}(boldsymbol{g}) ) is:
( mathbf{A} cdot C_{p N H_{3}}-left(C_{p N_{2}}right) )
B . ( 2 C_{p N H_{3}}-left(C_{p N_{2}}+3 C_{p H_{2}}right) )
( mathbf{c} cdot 2 C_{p N H_{3}}-left(C_{p H_{2}}right) )
D ( cdot 2 C_{p N H_{3}}+left(C_{p N_{2}}+3 C_{p H_{2}}right) )
11
66A volume of ( 2.5 ~ L ) of a sample of a gas
at ( 27^{circ} mathrm{C} ) and 1 bar pressure is
compressed to a volume of 500 ml keeping the temperature constant, the percentage increase in pressure is?
( mathbf{A} cdot 100 % )
B. ( 400 % )
c. ( 500 % )
D. ( 80 % )
11
67The average thermal energy of a oxygen atom at room temperature ( left(27^{circ} Cright) )
A ( cdot 4.5 times 10^{-21} J )
В. ( 6.2 times 10^{-21} J )
c. ( 3.4 times 10^{-21} J )
D. ( 1.8 times 10^{-21} mathrm{J} )
11
68When an ideal diatomic gas is heated
at constant pressure, the fraction of the heat energy supplied which increases
the internal energy of the gas is?
A. ( 2 / 5 )
B. 3/5
c. ( 3 / 7 )
D. ( 5 / 7 )
11
69The law of equipartition of energy is applicable to the system whose
constituents are :
A. in random motion
B. in orderly motion
c. at rest
D. moving with constant speedd
11
70The average kinetic energy of a molecule of a perfect gas is :
A ( cdot frac{2}{3} k T )
B. ( 1.5 k T )
c. ( 2.5 k T )
D. none of these
11
71If a gas mixture contains 2 moles of ( boldsymbol{O}_{2} )
and 4 moles of Ar at temperature ( T )
then what will be the total energy of the system (neglecting all vibrational modes)
A . 11 RT
B. 15 RT
c. 8 RT
D. RT
11
72An ideal gas having initial pressure ( P ) volume ( V ) and temperature ( T ) is allowed to expand adiabatically until its volume becomes ( 5.66 mathrm{V} ) while its temperature
falls to ( T / 2 . ) How many degrees of freedom do the gas molecules have?
A. 7
B. 5
( c cdot 6 )
D.
11
73One mole of a monoatomic gas is mixed with 3 mole of a diatomic gas. The
molar heat capacity at constant volume of mixture (in cal) is :
A . 4.5
B. 2
( c cdot 4 )
D.
11
74In Rutherford alpha particles scattering experiment, thin layer of which metal was used?
A. Aluminium
B. Gold
c. silver
D. zinç
11
75One half mole each of nitrogen, oxygen and carbon dioxide are mixed in
enclosure of volume 5 litres and
temperature ( 27^{circ} mathrm{C} . ) The pressure exerted by mixture is ( left(boldsymbol{R}=mathbf{8 . 3 1} boldsymbol{J} boldsymbol{m o l}^{-1} boldsymbol{K}^{-1}right) )
A ( cdot 7.48 times 10^{5} mathrm{N} mathrm{m}^{-2} )
B. ( 4 times 10^{5} mathrm{N} mathrm{m}^{-2} )
( mathbf{c} cdot 6 times 10^{5} mathrm{N} m^{-2} )
D. ( 3 times 10^{5} mathrm{N} m^{-2} )
11
76Volume of oxygen at NTP, required to
completely burn 1 kg of coal (100% arbon) is
A . 22.4 ( L )
В. ( 1.86 times 10^{3} mathrm{L} )
c. ( 22.4 times 10^{3} mathrm{L} )
D. 1000 L
11
77Calculate the means free path of
nitrogen molecule at ( 27^{circ} mathrm{C} ) when pressure is 1.0 atm. Given, diameter of nitrogen molecule ( =1.5 stackrel{o}{A}, k_{B}= )
( 1.38 times 10^{-23} J K^{-1} . ) If the average speed
of nitrogen molecule is ( 675 m s^{-1} ). The time taken by the molecule between two successive collisions is?
A. 0.6 ns
B. ( 0.4 mathrm{ns} )
c. ( 0.8 mathrm{ns} )
D. 0.3 ns
11
78The gas mixture constists of 3 moles of oxygen and 5 moles of argon at temperature ( T . ) Considering only
translational and rotational modes, the
total internal energy of the system is:
A . ( 12 R T )
в. ( 20 R T )
c. ( 15 R T )
D. ( 4 R T )
11
79A gas has a molecular diameter of ( 0.1 mathrm{m} ) It also has a mean free path of ( 2.25 mathrm{m} ) What is its density?
A ( cdot 10^{-3} )
B . ( 10^{-2} )
( mathbf{c} cdot 10^{-4} )
D. ( 10^{-5} )
11
80The value of rotational K.E. at
temperature T of one gram molecules of a diatomic gas will be-
11
81A vessel of volume ( V ) contains ( n_{1} ) moles
of oxygen and ( n_{2} ) moles of carbon dioxide
at absolute temperature T. The pressure of the mixture is
A. ( frac{left(n_{1}+n_{2}right) R T}{V} )
В. ( frac{left(n_{1}-n_{2}right) R T}{V} )
c. ( frac{n_{1} n_{2} R T}{V} )
D. ( frac{n_{1} R T}{n_{2} V} )
11
82Choose the only correct statement from
the following
A. The pressure of a gas is equal to the total kinetic energy of the molecules in a unit volume of the gas.
B. The product of pressure and volume of a gas is always constant.
C. The average kinetic energy of molecules of a gas is proportional to its absolute temperature.
D. The average kinetic energy of molecules of a gas is proportional to the square root of its absolute temperature.
11
83( p-frac{1}{v} ) graph for a gas under constant
temperature is
A. Straight line
B. Circle
c. hyperbola
D. parabola
11
84The average velocity of the molecules in a gas in equilibrium is
A. proportional to ( sqrt{T} )
B. proportional to T
C. proportional to ( T^{2} )
D. equal to zero
11
85Calculate the kinetic energy of 10 gram
of Argon molecules at ( 127^{circ} mathrm{C} ) [Universal gas constant ( boldsymbol{R}= ) ( 8320 J / ) mol ( K . ) Atomic weight of Argon
( =mathbf{4 0} k boldsymbol{g} / boldsymbol{m o l}] )
11
86A gas mixture consists of 2 moles of
oxygen and 4 moles of Argon at temperature T. Neglecting all vibrational modes, the total internal
energy of the system is?
A . ( 4 mathrm{RT} )
B. 9 RT
( c .11 R T )
D. 15RT
11
87The heat capacity of a diatomic gas is higher than that of a mono-atomic gas.If
true enter 1 else 0
11
88According to the Boltzmann’s law of equipartition of energy, the energy per degree of freedom and at a temperature
T K is :
A. (3/2) KT
B. (2/3) KT
c. кт
D. 1/2 KT
11
89( 28 g ) of ( N_{2} ) gas is contained in a flask at
a pressure 10 atm and at a
temperature of ( 57^{0} C . ) It is found that
due to leakage in the flask, the pressure is reduced to half and the temperature
reduced to ( 27^{0} ) C.The quantity of ( N_{2} ) gas
that leaked out is:
( mathbf{A} cdot frac{11}{20} mathrm{g} )
B. ( frac{80}{11} ) g
c. ( frac{5}{63} ) g
D. ( frac{63}{5} g )
11
90The mass of ( mathrm{O}_{2} ) molecule is 16 times that
( mathrm{H}_{2} ) molecule. The rms velocity of ( mathrm{O}_{2} )
molecule at room temperature ( mathrm{C}_{r m s} ). The
rms velocity of ( mathrm{H}_{2} ) molecule at the same
temperature will be:
A ( cdot frac{C_{r m s}}{16} )
в. ( frac{C_{r m s}}{4} )
( mathbf{c} cdot 4 C_{r m s} )
D. ( 16 C_{r m} )
11
91One mole of an ideal monoatomic gas is
mixed with 1 mole of an ideal diatomic
gas. The molar specific heat of the mixture at constant volume is :
A. 3 cal
B. 4 cal
( c cdot 8 ) cal
D. 9 cal
11
92Assertion
( V_{r m s} ) and ( V_{text {mean }} ) of gaseous molecules is nearly of the order of velocity of sound.
Reason
The sound travels in air because of
vibrational molecular motion.
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
11
93Assertion
In the formula ( P=frac{2}{3} E, ) the term ( E )
represents translational kinetic energy
per unit volume of gas.
Reason
In case of monoatomic gas
translational kinetic energy and total
kinetic energy are equal.
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
11
94When we cool a gas below its condensation point, the K.E. of its
molecules:
A . increases
B. decreases
c. remains the same
D. first decreases then increases
11
95The ( u_{r m s} ) of gas at ( 327^{circ} C ) is :
A ( cdot 611.66 frac{m}{s e c} )
В . ( 19342.44 frac{mathrm{m}}{mathrm{sec}} )
с. ( 1223.22 frac{m}{s e c} )
D. ( 96.71 frac{m}{s e c} )
11
96What is number of degrees of freedom
of an ideal diatomic molecule at
ordinary temperature?
A. 7
B. 6
( c cdot 5 )
D.
11
97Boyle’s law is valid for real gases at :
a) low pressure
b) high pressure
c) low temperature
d) high temperature
( A cdot a, c )
в. а,
( c cdot b, c )
D. b,
11
98The total kinetic energy of 8 litres of helium molecules at 5 atmosphere pressure will be
A. 6078 erg
B. 6078 Joule
( c .607 ) erg
D. 607 Joule
11
99In a thermodynamic system, working substance is ideal gas, its internal energy is in the form of
A. Kinetic energy
B. Kinetic and potential energy
c. Potential energy
D. None of the above
11
100A sample of an ideal gas is contained in
a cylinder. The volume of the gas is suddenly decreased. A student makes the following statements to explain the change in pressure of the gas.
I. The average kinetic energy of the gas atoms increases.
II. The atoms of the gas hit the walls of the cylinder more frequently.
III. Temperature of the gas remains unchanged. Which of these statements is true?
A. I and II only
B. I and III only
c. ॥ and III only
D. I, II and III
11
101A system consists of ( mathrm{N} ) particles, which have independent K relations among one another. The number of degrees of freedom of the system is given by :
( A cdot 3 N K )
B. N/3K
( c .3 mathrm{N} / mathrm{K} )
D. 3N – K
11
102Maxwell’s laws of distribution of
velocities shows that
A. the number of molecules with most probable velocity is very large
B. the number of molecules with most probable velocity is small
C. the number of molecules with most probable velocity is zero
D. the number of molecules with most probable velocity is exactly equal to 1
11
103( 24 mathrm{J} ) of heat are added to a gas in a container, and then the gas does 6 J of work on the walls of the container. What
is the change in internal energy for the gas?
A . – 30
B . – 18 J
c. 4 J
D. 18 J
E. 30
11
104000
voe
11
105At constant pressure, the ratio of
increase in volume for an ideal gas per degree rise in kelvin temperature to its
original volume is :
( A )
в. ( frac{1}{alpha} )
c. ( frac{1}{sqrt{alpha}} )
( D cdot sqrt{alpha} )
11
106Kinetic energy of a gas molecule depends on:
A. Volume
B. Temperature
c. Pressure
D. None of these
11
107What is the average translational kinetic energy of a molecule of an ideal
gas at temperature of ( 27^{circ} mathrm{C} )
11
108Energy of all molecules of a monatomic gas having a volume ( V ) and pressure ( P ) is
( frac{3}{2} boldsymbol{P} boldsymbol{V} ). The total translational kinetic energy of all molecules of a diatomic
gas at the same volume and pressure is
A ( cdot frac{1}{2} P V )
в. ( frac{3}{2} P V )
c. ( frac{5}{2} P V )
D. 3PV
11
1093 mole of ( A g ) is heated from ( 300 K ) to
1000 ( K ). Calculate ( Delta H ) when ( P=1 ) at ( m )
and ( C_{p}=23+0.01 T )
A. ( 62 k J / m o l )
B. ( 45 mathrm{kJ} / mathrm{mol} )
c. ( 38 k J / m o l )
D. ( 54 ~ k J / m o l )
11
110Choose the wrong options
This question has multiple correct options
A. Translation kinetic energy of all ideal gases at same temperature is same
B. In one degree of freedom all ideal gases has internal energy ( =frac{1}{2} R T )
C. Translational degree of freedom of all ideal gases is three
D. Translational kinetic energy of one mole of all ideal gases is ( frac{3}{2} R T )
11
111The initial internal energy of the gas in
container ‘A’, if the containers were at
room temperature ( 300 mathrm{K} ) initially-
A . 1406.25 cal
в. 1000 cal
c. 2812.5 cal
D. none of these
11
112The kinetic energy of 1 gram mole of a gas at normal temperature and pressure is ( (mathrm{R}=8.31 mathrm{J} / mathrm{mole}-mathrm{K}) )
A ( cdot 0.56 times 10^{4} J )
В. ( 1.3 times 10^{2} J )
c. ( 2.7 times 10^{2} J )
D. 3.4 ( times 10^{3} mathrm{J} )
11
113The specific heat of an ideal gas depends on temperature is-
A ( cdot frac{1}{T} )
в. ( T )
c. ( sqrt{T} )
D. Does not depend on temperature
11
114If the pressure of a gas is increased then its mean free path becomes:
A . zero
B. less
c. more
( D cdot alpha )
11
115A container is divided into two equal
parts I and II by a partition with a small
hole of diameter d. The two partitions are filled with same ideal gas, but held
at temperatures ( boldsymbol{T}_{boldsymbol{I}}=mathbf{1 5 0 K} ) and ( boldsymbol{T}_{boldsymbol{I I}}= )
( 300 K ) by connecting to heat reservoirs.
Let ( lambda_{I} ) and ( lambda_{I I} ) be the mean free paths of the gas particles in the two parts such
that ( boldsymbol{d}>>boldsymbol{lambda}_{boldsymbol{I}} ) and ( boldsymbol{d}>>boldsymbol{lambda}_{boldsymbol{I} I} . ) Then
( boldsymbol{lambda}_{I} / boldsymbol{lambda}_{I I} ) is close to.
( mathbf{A} cdot 0.25 )
B. 0.5
c. 0.7
D. 1.0
11
116If the pressure in a closed vessel is
reduced by drawing out some gas, the mean-free path of molecules:
A. is decreased
B. is increased
c. remains unchanged
D. increases or decreases according to the nature of the gas
11
117The mean free path and rms velocity of
a nitrogen molecule at a temperature ( 17 mathrm{C} ) are ( 1.2 times 10^{-7} mathrm{m} ) and
( 5 times 10^{2} mathrm{m} / mathrm{s} ) respectively.The time
between two successive collisions
A . ( 2.4 times 10^{-10} mathrm{s} )
B . ( 1.2 times 10^{-10} mathrm{s} )
c. ( 3.4 times 10^{-13} ) s
D. 3.4 ( times 10^{-10} ) s
11
118At what temperature will the linear kinetic energy of a gas molecule be
equal to that of an electron accelerated through a potential difference of ( 10 mathrm{V} ? )
( A cdot ) 273 ( k )
В . ( 19 times 10^{3} K )
c. ( 38.65 times 10^{3} )
D. ( 11.3 times 10^{3} K )
11
119The graph drawn between pressure and
volume in Boyle’s law experiment is
shown in figure for different masses of
same gas at same temperature then
( mathbf{A} cdot m_{2}>m_{1} )
В ( cdot m_{1}>m_{2} )
( mathbf{c} cdot m_{1}=m_{2} )
( mathbf{D} cdot m_{1}^{3}>m_{2} )
11
120A vessel contains a gas under a pressure of ( 5 times 10^{5} ) pa. If ( frac{3}{5} ) of the mass of the gas is
flown out,What will be the gas pressure if
the temperature being maintained constant.
A. 50 MPa
B. 2MPa
c. о.२мРа
D. 0.5MPa
11
121The average translational kinetic energy of air molecules is ( 0.040 e V )
( mathbf{1} e V=mathbf{1 . 6} times mathbf{1 0}^{-19} mathbf{J} ) ). Calculate the
temperature of the air. Boltzman’s
constant ( k=1.38 times 10^{-23} J K^{-1} )
11
122A closed vessel contains a mixture of two
gases Neon & Argon the total mass of mixture is 28 gm.The partial pressure due to Argon and neon are 4 atm and 12atm respectively.The mass of individual gases in vessel is ( left(M_{text {neon}}=right. )
( left.20, M_{text {argon}}=40, R=8.3 mathrm{J} / mathrm{mol}-mathrm{k}right) )
A. ( 4 mathrm{gm}, 24 mathrm{gm} )
B . ( 1 mathrm{gm}, 27 mathrm{gm} )
( mathrm{c} cdot 6 mathrm{gm}, 22 mathrm{gm} )
D. ( 2 g mathrm{m}, 26 mathrm{gm} )
11
123The pressure of a gas in a ( 100 mathrm{mL} ) container is ( 200 mathrm{kPa} ) and the average
translation kinetic energy of each gas particle is ( 6 times 10^{-21} ). Find the number
of gas particles in the container. How many moles are there in the container?
11
124One mole of an ideal gas ( left(C_{v, m}=frac{5}{2} Rright) ) at ( 300 mathrm{K} ) and 5 atm is expanded adiabatically to a final
pressure of 2 atm against a
constant pressure of 2 atm. Final temperature of the gas is:
( mathbf{A} cdot 270 mathrm{K} )
B. 273 к
c. ( 248.5 mathrm{k} )
D. 200 к
11
125Mean free path does not depend on
( A cdot rho )
B. T
( c cdot d )
D.
11
126Write the postulates of Dalton’s Atomic theory11
127Two rigid boxes containing different ideal gases are placed on a table. Box ( A )
contains one mole of ( N_{2} ) at temperature
( T_{0}, ) while box ( mathrm{B} ) contains one mole of ( boldsymbol{H}_{2} )
at temperature ( 7 / 3 T_{0} . ) The boxes
are then put into thermal contact with
each other and heat flows between them
until the gases reach a common final temperature [lgnore the heat capacity of boxes]. Then the final
temperature of the gases ( T_{f} ) in terms of
( boldsymbol{T}_{0} ) is
A ( cdot T_{f}=frac{5}{2} ) To
B ( T_{f}=frac{3}{7} T o )
c. ( T_{f}=frac{5}{3} ) To
D. ( T_{f}=frac{3}{2} ) To
11
128Two balloons are filled, one with pure He gas and the other by air, respectively. If the pressure and temperature of these
baloons are same then the number of
molecules per unit volume is:
A. More in the He filled balloon
B. Same in both balloons
c. More in air filled balloon
D. In the ratio of 1: 4
11
129To find out degree of freedom, the correct expression is :
A ( cdot f=frac{2}{gamma-1} )
B. ( f=frac{gamma+1}{2} )
( ^{mathbf{C}} f=frac{2}{gamma+1} )
D. ( f=frac{1}{gamma+1} )
11
130Calculate ( gammaleft(text { ratio of } C_{p} text { and } C_{v}right) ) for triatomic linear gas at high
temperature. Assume that the
contribution of the vibrational degree of freedom is ( 75 % ? )
A. 1.222
B. 1.121
c. 1.18
D. 1.33
11
131A bullet travelling at ( 100 mathrm{ms}^{-1} ) suddenly hits a concrete wall. If its K.E. is
converted completely into heat, the
raise in temperature is
( left(s=100 J k g^{-1} K^{-1}right) )
A. 20k
в. 40k
( c . ) 50k
D. 60k
11
132A gas has an average speed of ( 10 mathrm{m} / mathrm{s} )
and a collision frequency of ( 10 s^{-1} . ) What
is its mean free path?
A. ( 1 m )
в. ( 2 m )
c. ( 3 m^{text {- }} )
D. ( 4 m )
11
133The value of universal gas constant is
( 8.3 J / )mole( / K, ) the mean kinetic
energy of ( 32 g m ) of oxygen at ( -73^{circ} C ) will
be
( mathbf{A} cdot 480 J )
в. ( 4980 J )
c. ( 2490 J )
D. ( 100 J )
11
134The average kinetic energy of ( O_{2} ) at a
particular temperatures is ( 0.768 mathrm{eV} )
The average kinetic energy of ( N_{2} ) molecules in eV at the same
temperature is?
A . 0.0015
B. 0.0030
c. 0.048
D. 0.768
11
135A column of ( mathrm{Hg} ) of ( 10 mathrm{cm} ) length is contained in the middle of a narrow
horizontal ( 1 mathrm{m} ) long tube which is closed at both ends. Both the halves of the tube
contain air at a pressure ( 76 mathrm{cm} ) of Hg. The distance of the column of Hg be
displaced if the tube is held vertically is
A. 3 cms
B. 2 cms
c. ( 4 mathrm{cms} )
D. ( 1 mathrm{cm} )
11
136From which height a block of ice must be dropped in order that it melts completely. Assume that all the energy
is retained by the ice. ( left(g=10 m s^{-2}, L=80 J g m^{-1} a n d J=4.2right. )
( mathrm{J} / mathrm{cal} )
A. ( 1000 mathrm{Km} )
B. 100Km
c. 33.6кm
D. ( 1 mathrm{Km} )
11
1373 mole of gas “X” and 2 moles of gas “Y” enters from end “P” and “Q” of the cylinder respectively. The cylinder has the area of cross section, shown as
under
The length of the cylinder is ( 150 mathrm{cm} ). The gas “X” intermixes with gas “Y” at the point. If the molecular weight of the
gases ( X ) and ( Y ) is 20 and 80 respectively, then what will be the distance of point ( mathbf{A} )
from Q?
A. ( 75 mathrm{cm} )
B. ( 50 mathrm{cm} )
c. 37.5
D. ( 90 mathrm{cm} )
11
138( C_{p}-C_{v} ) for an ideal gas is11
139Identify the best graph which
represents the relationship between the
average kinetic energy of the molecules
of a gas and its temperature?
( A )
B.
( c )
D.
E .
11
140A rigid container of negligible heat capacity contains one mole of an ideal gas. The temperature of the gas
increase by ( 1^{circ} mathrm{C} ) if ( 3 cdot 0 ) cal of heat is
added to it. The gas may be This question has multiple correct options
A. helium
B. argon
c. oxygen
D. carbon dioxide
11
141N’ molecules each of mass ‘m’, of gas A
and ‘2N’ molecules, each of mass ‘2m’,
of gas ( mathrm{B} ) are contained in the same vessel. Which is maintained at a
temperature T. The mean square of the velocity of molecules of B type is
denoted by ( V^{2} ) and the mean square of the ( X ) component of the velocity of ( A ) type is denoted by ( omega^{2}, frac{omega^{2}}{V^{2}}= )
( A cdot 2 )
B.
( c cdot 1 / 3 )
( D cdot 2 / 3 )
11
142If the pressure of an ideal gas contained in a closed vessel is increased by ( 0.4 % )
the increases in temperature is ( 1^{circ} mathrm{C} ) The initial temperature of the gas is:
( mathbf{A} cdot 26^{circ} C )
B . ( 250^{circ} mathrm{C} )
c. ( 250 K )
D. ( 2500^{circ} mathrm{C} )
11
143An enclosure of volume 3 litre contains 16
( mathrm{gms} ) of oxygen, ( 7 mathrm{gms} ) of nitrogen and 11 gms of carbon di-oxide at ( 27^{circ} mathrm{C} ). The
pressure exerted by the mixture is approximately
A. 1 atmosphere
B. 3 atmosphere
c. 9 atmosphere
D. 8.3 atmosphere
11
144In Boyles experiment for a given gas at
different temperatures the graph drawn
between pressure and density are
straight lines as shown then:
A ( cdot T_{1}>T_{2} )
в. ( T_{2}>T_{1} )
( mathrm{c} cdot T_{1}=T_{2} )
D. ( T_{1}^{3}=T_{2} )
11
145Consider the following statements for air molecules in an air tight container.
(I) The average speed of molecules is larger than root mean square speed.
(II) Mean free path of molecules is larger than the mean distance between molecules.
(III) Mean free path of molecules increases with temperature
(IV) The rms speed of nitrogen molecule is smaller than oxygen molecule. The
true statements are.
A. Only II
B. ॥ & ॥ I
c. ॥ & ।
D. I, II & IV
11
146Assertion
If a gas container is placed in a moving
train, the temperature of gas will increase.
Reason
Kinetic energy of gas molecules will increase.
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
11
147A closed vessel contains some gas at
atmospheric pressure and room
temperature. It is then given a high speed
by placing it in a fast moving train. The
temperature of the gas
A. will increase
B. will decrease
c. will remain uncharged
D. increase or decrease depending on the chemical composition of gas
11
148A man is climbing up a spiral type staircase. His degrees of freedom are :
( mathbf{A} cdot mathbf{1} )
B. 2
( c cdot 3 )
D. more than 3
11
149The average speed of all the molecules
in a gas at a given instant is zero,
whereas the average velocity of all the molecules is zero. Explain why?
11
150For any distribution of speeds ( V_{r m s} geq )
( V_{a v} . ) Is this statement true or false?
11
151The expression for mean free path is :
A ( cdot lambda=frac{K T}{sqrt{2} pi d^{2} P} )
B. ( lambda=frac{pi d P}{k T} )
c. ( _{lambda}=frac{pi d^{2} P}{k T} )
D. ( lambda=frac{k T}{pi d P} )
11
152The total kinetic energy of 1 mole of ( N_{2} )
at ( 27^{circ} C ) will be approximately:
A . ( 1500 J )
B. 1500 calorie
c. 1500 kilo calorie
D. 1500 erg
11
153A spherical balloon rises up and the
radius become twice that on the ground.
Assuming temperature to be constant
the pressure at that altitude is
A. ( 1 / 3 ) rd of that on the earth
B. ( 1 / ) 9th that on the earth’s surface
C. ( 1 / 8 ) times of that on the earth’s surface
D. 3 times of that on the surface of the earth
11
154An air bubble rises from the bottom to
the surface of lake and it is found that
its diameter is doubled. If the height of water barometer is ( 11 mathrm{m} ), the depth of the lake in meters is
A. ( 70 mathrm{m} )
B. 77m
( c .7 .7 mathrm{m} )
D. 78m
11
155For which of the following ideal gas
( C_{V, m} ) is independent of temperature?
A. ( H e )
в. ( H_{2} )
c. ( C O )
( mathrm{D} cdot mathrm{SO}_{2} )
11
156Water is falling from 160m height. Assuming that half the K.E. of falling water gets converted into heat, the rise
in temperature of water is approximately
( mathbf{A} cdot 0.1^{0} C )
B. ( 0.2^{0} C )
( mathbf{c} cdot 0.3^{0} C )
D. ( 0.4^{circ} mathrm{C} )
11
157From what minimum height, a block of ice has to be dropped in order that it may melt completely on hitting the
ground:
( A cdot m g h )
в. ( frac{m g h}{l} )
c. ( frac{l}{g} )
D. ( frac{h}{l g} )
11
158Variation of ( Delta boldsymbol{H} ) vs temperature is given by:
A. Kirchhoff’s equation
B. Gibbs-Helmholtz equation
c. Clausius-Clapeyron equation
D. Van’t Hoff’s equation
11
159Which of the following is an assumption of Kinetic theory of matter?
A. Molecules are in a state of continuous motion and possess kinetic energy
B. The kinetic energy of molecules increases with increase in temperature.
c. The molecules of matter always attract each other due to forces of cohesion and adhesion
D. All of the above
11
160The heat capacity of a certain amount
of a particular gas at constant pressure
is greater than that at constant volume by ( 29.1 mathrm{J} / mathrm{K} . ) Match the items given in
Column I with the items given in Column II.
List 1
If the gas is monatomic, heat capacity at constant volume

If the gas monatomic, heat capacity at constant pressure
If the gas is rigid diatomic, heat capacity at constant pressure
If the gas is vibrating diatomic, heat capacity at constant pressure
( mathbf{A} cdot A rightarrow 2, B rightarrow 3, C rightarrow 4, D rightarrow 1 )
B. ( mathrm{B} rightarrow 1, mathrm{C} rightarrow 3, mathrm{D} rightarrow 4, mathrm{A} rightarrow 1 )
C. ( mathrm{C} rightarrow 1, mathrm{D} rightarrow 3, mathrm{A} rightarrow 4, mathrm{B} rightarrow 1 )
D. ( D rightarrow 1, A rightarrow 3, B rightarrow 4, C rightarrow 1 )

11
161Two metal balls of same material
having masses ( 50 mathrm{gm} ) and ( 100 mathrm{gm} ) collides with a target with
same velocity. Then the ratio of their rise in temperature is
A . 1: 2
B. 4:
c. 2:
D. 1:
11
162The ratio of average translational kinetic energy to rotational kinetic energy of a diatomic molecule at
temperature ( mathrm{T} ) is ( mathrm{x} / mathrm{y} ) then value of ( x+y ) is
11
163A gas in a ( 1 mathrm{m}^{3} ) container has a
molecular diameter of ( 0.1 mathrm{m} . ) There are 10 molecules. What is its mean free
path?
A . ( 2.25 mathrm{m} )
B. 2m
( c .3 m )
( D cdot 1 m )
11
164A vessel of volume 4 litres contains a
mixture of 8 gms of ( mathrm{O}_{2}, 14 ) gms of ( mathrm{N}_{2} ) and
22 gms of ( mathrm{CO}_{2} ) at ( 27^{0} mathrm{C} ). The pressure
exerted by the mixture is
A. 10 atmosphere
B. ( 5 times 10^{6} mathrm{N} / mathrm{m}^{2} )
C ( .7 .79 times 10^{5} mathrm{N} / mathrm{m}^{2} )
D. ( 6 times 10^{5} 5 mathrm{N} / mathrm{m}^{2} )
11
165Energy of all molecules of a monatomic
gas having a volume ( V ) and pressure ( P ) is ( frac{3}{2} P V . ) The total translational kinetic energy of all molecules of a diatomic
gas at the same volume and pressure is
A ( cdot frac{1}{2} P V )
в. ( frac{3}{2} P V )
c. ( frac{5}{2} P V )
D. 3 PV
11
166If an air bubble rises from the bottom of
the lake to its surface at constant
temparature, its volume
A . decreases
B. increases
c. remain same
D. can’t say
11
167In a thermodynamic process, helium gas obeys the law, ( boldsymbol{T} boldsymbol{P}^{-2 / 5}= ) constant.
The heat is given to ( n ) moles of ( H e ) in
order to raise the temperature from ( boldsymbol{T} ) to
( mathbf{2} T ) is :
( A cdot 8 R T )
в. ( 4 R T )
c. ( 16 R T )
D. Zero
11
168The average kinetic energy of the particles of a gas is most closely associated with which of the following quantity?
A. heat capacity.
B. temperature
c. specific heat
D. absolute zero.
E. potential enemy.
11
169What is the name of ( h & ) what is the
value?
11
170Ten small planes are flying at a speed of ( 150 mathrm{km} h^{-1} ) in total darkness in an air
space that is ( 20 times 20 times 1.5 k m^{3} ) in
volume. You are in one of the planes, flying at random within this space with no way of knowing where the other planes are. On the average about how long a time will elapse between near collision with your plane. Assume for this rough computation that a safety region around the plane can be approximated by a sphere of radius 10
( mathrm{m} )
A. 125 h
в. 220h
c. 432 h
D. 225h
11
171A vertical hollow cylinder of height ( 1.52 mathrm{m} ) is fitted with a movable piston of
negligible mass and thickness. The lower
half portion of the cylinder contains an
ideal gas and the upper half is filled with
mercury. The cylinder is initially at ( 300 mathrm{K} )
When the temperature is raised half of
the mercury comes out of the cylinder. Then the temperature is (the thermal
expansion of mercury to be negligible)
( A cdot 437 mathrm{K} )
B. 337.5 K
c. ( 275 mathrm{k} )
D. 137.K
11
172Explain the inter-conversion of the three
states of matter in terms of force
attraction and K.E of the molecules.
11
173At what temperature the rms velocity of
helium molecules will be equal to that of
hydrogen molecules at NTP?
A . ( 844 k )
B. 64 K
c. ( 273^{0} mathrm{C} )
D. 273k
11
174The heat capacity of liquid water is ( mathbf{7 5 . 6 J} / boldsymbol{K}-boldsymbol{m o l}, ) while the enthalpy of
fusion of ice is ( 6.0 k J / ) mol. What is the
smallest number of ice cubes at ( 0^{circ} C )
each containing ( 9.0 g ) of water, needed
to cool ( 500 g ) of liquid water from ( 20^{circ} mathrm{C} )
to ( 0^{circ} C ? )
A . 1
B. 7
c. 14
D. 21
11
175When the temperature is increased
from ( 0^{circ} mathrm{C} ) to ( 273^{circ} mathrm{C}, ) in what ratio the
average kinetic energy of molecules changes?
A.
B. 5
( c cdot 4 )
( D cdot 2 )
11
176The mass of hydrogen molecule us ( 3.32 x ) ( 10^{-27} ) kg.If ( 10^{23} ) hydrogen molecules
strike per second at ( 2 mathrm{cm}^{2} ) area of a rigid
wall at an angle ( 45^{0} ) from the normal and
rebound back with speed of ( 1000 mathrm{m} / mathrm{s} )
then the pressure exerted on the wall is
A. 2 Pascal
B. 2.34 times 10 ( ^{3} ) Pascal
c. ( 0.23 times 10^{3} ) Pascal
D. 23.4 x 10 ( ^{3} ) Pascal
11
177If the kinetic energy of the molecules in 5 litres of helium at 2 at ( m ) is ( E ). What is
the kinetic energy of molecules in 15
litres of oxygen at 3 at ( m ) in terms of ( E ? )
A . ( 7.5 E )
в. ( 7 E )
( c .8 .5 E )
D. ( 8 E )
11
178The poisson’s ratio for ( O_{2} ) is ( 1.4 . ) Which
of the following are correct for ( O_{2} ? )
This question has multiple correct options
A. ( C_{V M}=5 c a l )
В. ( C_{V}=0.156 mathrm{cal} )
( mathbf{c} cdot C_{P}=frac{R Upsilon}{Upsilon-1} )
D. ( C_{V}=frac{R}{(Upsilon-1)} )
11
179A gas mixture consists of 2 moles of
oxygen and 4 moles of Argon at temperature T. Neglecting all
vibrational moles, the total internal
energy of the system is
A . ( 4 mathrm{RT} )
в. 15RT
c. 9 RT
D. 11RT
11
180If the total number of ( boldsymbol{H}_{2} ) molecules is
double of the ( O_{2} ) molecules then the
ratio of total kinetic energies pf ( boldsymbol{H}_{2} ) to
that of ( O_{2} ) at ( 300 mathrm{K} ) is :
A .1: 1
B. 1: 2
( c cdot 2: )
( D cdot 1: 3 )
11
181The amount of heat energy required to raise the temperature of ( 1 g ) of helium
in a container of volume ( 10 L, ) from ( T_{1} K )
to ( T_{2} K ) is ( left(N_{a}= ) Avogadros number, right.
( k_{B}= ) Boltzmann constant
A ( cdot frac{3}{2} N_{a} k_{B}left(T_{2}-T_{1}right) )
в. ( frac{3}{7} N_{a} k_{B}left(T_{2}-T_{1}right) )
c. ( frac{3}{4} N_{a} k_{B}left(T_{2}-T_{1}right) )
D ( cdot frac{3}{8} N_{a} k_{B}left(T_{2}-T_{1}right) )
11
182A flask contains argon and chlorine in
the ratio of 2: 1 by mass. The
temperature of the mixture is ( 27^{0} C . ) The ratio of average kinetic energies of two gases per molecule is
A . 1: 1
в. 2: 1
( c .3: 1 )
D. 6: 1
11
183The internal energy of a gas:
( A . ) is the sum total of kinetic and potential energies.
B. is the total transitional kinetic energies
C . is the total kinetic energy of randomly moving molecules.
D. is the total kinetic energy of gas molecules
11
184A sample of helium gas is at a temperature of ( 300 mathrm{K} ) and a pressure of 0.5 atm. What is the average kinetic
energy of a molecule of a gas?
11
185If the average kinetic energy of a molecule of a hydrogen gas at ( 300 mathrm{K} ) is ( mathrm{E} ) then the average kinetic energy of a molecule of a nitrogen gas at the same temperature is:
A . ( 7 mathrm{E} )
в. ( E / 14 )
( c .14 E )
D. ( E / 7 )
( E . )
11
186The total Kinetic energy of 1 mole of ( N_{2} )
at ( 27^{circ} C ) will be approximately :-
A . ( 1500 J )
B . 15633 cal
c. ( 1500 mathrm{kcal} )
D. 1500 erg
11
187Two glass bulbs of volumes ( 500 mathrm{cm}^{3} )
and ( 200 mathrm{cm}^{3} ) are connected with a narrow
tube. Both of them are filled with air at
70mm of ( mathrm{Hg} ) and at ( 17^{circ} mathrm{C} ) and sealed. The
bulb of small volume is kept in ice and the other with larger volume is kept in steam. Then find the pressure of the gas in the bulb.
A. ( 51 mathrm{mm} ) of ( mathrm{Hg} )
B. 200cm of Hg
c. 873mm of Hg
D. 200m of Hg
11
188If for a gas ( frac{boldsymbol{R}}{boldsymbol{C}_{boldsymbol{v}}}=mathbf{0 . 6 7}, ) then the gas is
made up of molecules which are :
A. Diatomic
B. Monoatomic
c. Polyatomic
D. Mixture of Diatomic & Polyatomic
11
189The ratio of a specific heats of a gas is ( 9 / 7, ) then the number of degrees of
freedom of the gas molecules for translation motion is:
11
190f ( mathrm{K} ) is the average kinetic energy per atom, find ( x, ) such that ( x=K times 10^{23} )11
191A gas has an average speed of ( 10 m / s )
and a collision frequency of ( 10 s^{-1} )
What is its mean free path?
A. ( 1 m )
в. ( 2 m )
( c .3 m )
D. ( 0.1 m )
11
192A barometer reads ( 75 mathrm{cm} ) of Hg. When
( 2 mathrm{cc} ) of air at atmpospheric pressure is introduced into the space above the mercury level, the volume of this space becomes 50 cc. The length by which the mercury column descends is
A. ( 3 mathrm{cm} )
B. 6 ( mathrm{cm} )
c. ( 1.5 mathrm{cm} )
D. 25 cm
11
193A vessel contains a mixture consisting
of ( m_{1}-7 g ) of nitrogen ( left(M_{1}=28right) ) and ( m_{2}= )
11 g of carbon dioxide ( left(M_{2}=44right) ) at
temperature ( T-300 K ) and pressure ( P_{0}= ) atm. The density of the mixture is
A. ( 1.46 g ) per litre
B. ( 2.567 g ) per litre
c. ( 3.752 g ) per litre
D. ( 4.572 g ) per litre
11
194The most probable velocity for monoatomic gas is
A ( cdot sqrt{frac{3 k T}{m}} )
в. ( sqrt{frac{8 k T}{pi m}} )
c. ( sqrt{frac{2 k T}{m}} )
D. zero
11
195A mercury barometer is known to be defective. It contains a small quantity of air in the space above the mercury. When an accurate barometer reads 770
( mathrm{mm}, ) the defective one reads ( 760 mathrm{mm} )
and when the accurate one reads 750
( mathrm{mm}, ) the defective one reads ( 742 mathrm{mm} )
The true atmospheric pressure when the defective barometer reads ( 750 mathrm{mm} )
is
A. ( 68 mathrm{cm} ) of ( mathrm{Hg} )
в. ( 79.88 mathrm{cm} ) of ( mathrm{Hg} )
( c .75 .88 mathrm{cm} ) of ( mathrm{Hg} )
D. 72.15 cm of Hg
11
196The mean kinetic energy of a gas
molecule is proportional to
( mathbf{A} cdot sqrt{T} )
B . ( T^{3} )
( c . T )
D. None of the above
11
197A thin tube of uniform cross-section is
sealed at both ends. It lies horizontally,
the middle ( 5 mathrm{cm} ) containing mercury and
the two equal ends containing air at the
same pressure ( P_{o} . ) When the tube is held
at an angle ( 60^{circ} ) with the vertical, the
lengths of the air column above and
below the mercury are 46 and ( 44.5 mathrm{cm} )
respectively. The pressure ( P_{o} ) in ( mathrm{cm} ) of ( mathrm{Hg} )
is: (The temperature of the system is left at ( 30 mathrm{K} )
A. 80 cm of ( H g )
B. ( 75.4 mathrm{cm} ) of ( mathrm{Hg} )
c. 70 cm of ( H g )
D. 90 cm of ( H g )
11
198Assertion
Vibrational energy of diatomic molecule corresponding to each degree of
freedom is ( k_{B} T )
Reason
For every molecule, vibrational degree of freedom is 2
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
11
199A gaseous mixture enclosed in a vessel
consists of one ( g ) mole of a gas ( A ) with ( gamma=left(frac{5}{3}right) ) and some amount of gas ( mathrm{B} ) with ( gamma=frac{7}{5} ) at a temperature The
gasses ( A ) and ( B ) do not react with each
other and are assumed to be ideal Find
the number of ( g ) moles of the gas ( B ) if ( gamma ) for the gaseous mixture is ( left(frac{19}{13}right) )
( A cdot 2 )
( B .5 )
( c cdot 4 )
D. 3
11
200A vessel of volume ( V ) contains a mixture
of 1 mole of hydrogen and 1 mole of oxygen(both considered as ideal). Let
( f_{1}(v) d v ) denote the fraction of
molecules with speed between v and
( (boldsymbol{v}+boldsymbol{d} boldsymbol{v}) ) with ( boldsymbol{f}_{2}(boldsymbol{v}) boldsymbol{d} boldsymbol{v}, ) similarly for
oxygen. then
( mathbf{A} cdot f_{1}(v)+f_{2}(v)=f(v) ) obeys the Maxwell’s distribution law
B. ( f_{1}(v), f_{2}(v) ) will obey the Maxwell’s distribution law separately
C. Neither ( f_{1}(v) ) nor ( f_{2}(v) ) will obey the Maxwell’s distribution law
D. ( f_{2}(v) ) and ( f_{1}(v) ) will be the same
11
201Significant motion for the molecules of a monoatomic gas corresponds to :
A. translatory
B. vibratory
c. rotatory
D. none of these
11
202A diatomic gas is heated at certain pressure. What fraction of the heat energy is used to increase the internal
energy?
A ( .3 / 5 )
B. ( 3 / 7 )
c. ( 5 / 7 )
D. ( 5 / 9 )
11
203At constant temperature and pressure,
the volume of a given gas is related to
mass as
A. Volume is not related to mass
B ( cdot v propto frac{1}{m} )
c. ( v propto-frac{1}{m} )
D. ( v propto m )
11
204Pressure of an ideal gas is increased by keeping temperature constant. What is effect on kinetic energy of molecules?
A. Increase
B. Decrease
c. No change
D. Cannot be determined
11
205State the law of equipartition of energy11
206A barometer reads ( 75 mathrm{cm} ) of mercury.
When ( 2.0 mathrm{cm}^{3} ) of air at atmospheric
pressure is introduced into space above the mercury level, the volume of the space becomes ( 50 mathrm{cm}^{3} ). The length
by which the mercury column descends is
A. ( 3 mathrm{cm} ) of ( mathrm{Hg} )
B. ( 6 mathrm{cm} ) of ( mathrm{Hg} )
c. ( 30 mathrm{cm} ) of ( mathrm{Hg} )
D. ( 10 mathrm{cm} ) of ( mathrm{Hg} )
11
207The graph drawn between pressure and
volume in Boyle’s law experiment is
shown in figure for two different gases. If the same amount of both the gases has
been taken, then the relationship between their molecular weights will be
A ( . M_{2}<M_{1} )
( mathbf{B} cdot M_{1}<M_{2} )
( mathbf{c} cdot M_{1}=M_{2} )
( mathbf{D} cdot M_{1}^{3}=M_{2} )
11
208If for a gas ( frac{boldsymbol{R}}{boldsymbol{C}_{boldsymbol{V}}}=mathbf{0 . 6 7}, ) this gas is made
up of molecules which are.
A. Monatomic
B. Diatomic
c. Polyatomic
D. Mixture of diatomic and polyatomic molecules
11
209The internal energy of one gram of
helium at ( 100 mathrm{K} ) and one atmospheric pressure is?
A . 100
B . 1200 J
c. 300
D. 500
11
210Estimate the mean free path of a
cosmic ray proton in the atmosphere at sea level. Given ( sigma=10^{-26} mathrm{cm}^{2} )
( mathbf{A} cdot 10^{4} c m )
B. ( 10^{-4} mathrm{cm} )
( mathbf{c} cdot 10^{6} c m )
D. ( 10^{-6} mathrm{cm} )
11
211Figure shows the variation of the
internal energy ( U ) with density ( rho ) of one
mole of an ideal monatomic gas for thermodynamic cycle ABCA. Here process ( A B ) is a part of rectangular
hyperbola
A. process AB is isothermal & net work in cycle is done
on gas
B. process AB is isothermal & net work in cycle is done by the gas
c. process AB is isobaric & net work in cycle is done on the gas
D. process AB is adiabatic & net work in cycle is done by
gas
11
212( N^{prime} ) moles of a diatomic gas in a
cylinder are at a temperature ( ^{prime} boldsymbol{T}^{prime} . ) Heat
is supplied to the cylinder such that the
temperature remains constant but ( n )
moles of the diatomic gas get converted
into monatomic gas.What is the change in the total kinetic energy of the
gas?
A ( cdot frac{5}{2} n R T )
B. ( frac{1}{2} n R T )
c. 0
D. ( frac{3}{2} n R T )
11
213Match List I and List II
List-I List-II
a) Barometer
e) Charles law
b) specific gas constant
( f ) ) ( J m o l e^{-1} K )
-1
c) gas thermometer
g) Boyels law
d) universal gas constant
h) ( operatorname{JKg}^{-1} mathrm{K}^{-1} )
A. a-h,b-e,c-f, d-g.
B. a-g, b-h, c-e,d-f.
c. a-f, b-g,c-h,d-e.
D. ( a-f, b-e, c-h, d-g . )
11
214The kinetic energy of ( 1 g ) molecule of a
gas at normal temperature and
pressure is :
( mathbf{A} cdot 1.3 times 10^{2} J )
B . ( 2.7 times 10^{2} J )
c. ( 0.56 times 10^{4} J )
D. ( 3.4 times 10^{3} J )
11
215Liquid is filled in a vessel which is kept
in a room with temperature ( 20^{circ} mathrm{C} ). When
the temperature of the liquid is ( 80^{circ} C ) then it losses heat at the rate of 60
cal/sec.What will be the rate of loss of
heat when the temperature of the liquid
is ( 40^{circ} mathrm{C} )
A . 180 cal / sec
B . 40 cal/sec
c. 30 cal/sec
D. 20 cal/sec
11
216At constant pressure, the heat of
formation of a compound is not dependent on temperature, when:
( mathbf{A} cdot Delta C_{p}=0 )
В. ( Delta C_{v}=0 )
( mathbf{c} cdot Delta C_{p}>0 )
D. ( Delta C_{p}<0 )
11
217The mean free path of a molecule of He
gas is a its mean free path along any arbitary coordinate axis will be.
11
218The mean free path of the molecule of a
certain gas at ( 300 mathrm{K} ) is ( 2.6 times 10^{-5} mathrm{m} )
The collision diameter of the molecule
is ( 0.26 mathrm{nm} . ) Calculate
(a) pressure of the gas, and
(b) number of molecules per unit
volume of the gas.
B. (a) ( 1.281 times 10^{22} mathrm{m}^{-3} ) (b) ( 5.306 times 10^{3} mathrm{Pa} )
D. (a) 2.56 ( times 10^{23} mathrm{m}^{-3} ) (b) ( 10.612 times 10^{2} mathrm{Pa} )
11
219( N_{2} ) gas is assumed to behave ideally ( A )
given volume of ( N_{2} ) originally at ( 373 mathrm{k} )
and 0.1013 M pa pressure is adiabatically compressed due to which
its temperature rises to ( mathbf{6 7 3} boldsymbol{K}left(boldsymbol{C v}=frac{mathbf{5}}{mathbf{2}} boldsymbol{R}right) )
Which of the following statement(s) is/are correct?
This question has multiple correct options
A. The change in internal energy is 6235.5 J mole ( ^{-1} )
B. In this case the final internal pressure is equal to the external pressure
C. The final pressure of ( N_{2} ) is approximately 0.38 MPa
D. The final pressure of ( N_{2} ) is approximately 0.02 Mpa
11
220When an ideal diatomic gas is heated at constant pressure, the fraction of the heat energy supplied which increase the internal energy of gas is?
( A cdot frac{2}{5} )
B.
( c cdot frac{3}{7} )
( D cdot frac{5}{7} )
11
221The mean free path of molecules of a gas (radius ‘r’) is inversely proportional
to
A ( cdot r^{3} )
В ( cdot r^{2} )
( c cdot r )
D. ( sqrt{r} )
11
222The mass of hydrogen molecule us ( 3.32 x ) ( 10^{-27} ) kg.If ( 10^{23} ) hydrogen molecules
strike per second at ( 2 mathrm{cm}^{2} ) area of a rigid
wall at an angle ( 45^{0} ) from the normal and
rebound back with speed of ( 1000 mathrm{m} / mathrm{s} )
then the pressure exerted on the wall is
A. 2 Pascal
B. 2.34 times 10 ( ^{3} ) Pascal
c. ( 0.23 times 10^{3} ) Pascal
D. 23.4 x 10 ( ^{3} ) Pascal
11
223Oxygen is filled in a closed metal jar of volume ( 1.0 times 10^{-3} m^{3} ) at a pressure of
( 1.5 times 10^{5} ) Pa and temperature ( 400 K )
The jar has a small leak in it. The
atmospheric pressure is ( 1.0 times 10^{5} mathrm{Pa} )
and the atmospheric temperature is ( 300 K . ) Find the mass of the gas that
leaks out by the time the pressure and the temperature inside the jar equalize with the surrounding.
11
224In the nuclear fusion reaction, ( _{1}^{2} mathbf{H}+_{1}^{3} ) ( mathbf{H} rightarrow_{2}^{4} H e+n ) given that the repulsive potential energy between the two nuclei is ( 7.7 times 10^{-14} J, ) the temperature at
which the gases must be heated to initiate the reaction is nearly [Boltzmann’s constant ( mathbf{k}=mathbf{1 . 3 8} times )
( left.mathbf{1 0}^{-mathbf{2 3} mathbf{J}} / mathbf{K}right] )
( mathbf{A} cdot 10^{7} K )
В. ( 10^{5} K )
( mathbf{c} cdot 10^{3} K )
( mathbf{D} cdot 10^{9} K )
11
225Two moles of an ideal monoatomic gas
at ( 27^{circ} mathrm{C} ) occupies a volume of ( V ). If the
gas is expanded adiabatically to the
volume ( 2 V ), then the work?
11
226There are two vessels of same
consisting same no of moles of two different gases at same temperature.
One of the gas is ( C H_{4} & ) the other is
unknown X. Assuming that all the molecules of ( X ) are under random
motion whereas in ( C H_{4} ) except one all
are stationary. Calculate ( Z_{1} ) for ( X ) in
terms of ( Z_{1} ) of ( C H_{4} . ) Given that the collision diameter for both gases are same ( &left(U_{r m s}right)_{x}=frac{1}{sqrt{6}}(U a v)_{C H_{4}} )
A ( cdot frac{2 sqrt{2}}{3 sqrt{pi}} Z_{1} )
B ( cdot frac{3 sqrt{2}}{2 sqrt{pi}} Z_{1} )
c. ( frac{2 sqrt{3}}{2 sqrt{pi}} Z_{1} )
D. ( frac{4 sqrt{2}}{3 sqrt{pi}} Z_{1} )
11
227For a given gas, which of the following relationships is correct at a given temp?
( mathbf{A} cdot u_{r m s}>u_{a v}>u_{m p} )
B . ( u_{r m s}<u_{a v}u_{a v}<u_{m p} )
D. ( u_{r m s}u_{m p} )
11
228A drop of alcohol is introduced into the
vaccum space of mercury barometer completely evaporates and then slightly lowers the height of the barometer. If the barometer tube is raised from this
position, the height of the barometer will
A. fall
B. rise
C. remains stationery
D. falls first and then rises
11
229A piece of lead falls from a height of 100m on a fixed non-conducting slab which brings it to rest. The temperature of the lead piece immediately after collision increases by (Sp.heat of lead
is ( 30.6 mathrm{cal} / mathrm{kg} /^{0} C ) and ( g=9.8 m / s e c^{2} . )
( A cdot ) ок
в. ( 27^{circ} mathrm{C} )
c. ( 7.62 k )
D. 4.2k
11
230Which of the following quantities is the
same for all ideal gases at the same temperature? This question has multiple correct options
A. The kinetic energy of 1 molecule
B. The kinetic energy of ( 1 mathrm{g} )
c. The number of the molecules in 1 mole
D. The number of molecules in 1 ( g )
11
231What is the total random translational
energy of the molecules in one mole of
this gas?
11
232The number of degrees of freedom for each atom of a monoatomic gas is :
( A cdot 3 )
B. 5
( c cdot 6 )
( D )
11
233One mole of an ideal monoatomic gas is
heated at a constant pressure from ( 0^{circ} mathrm{C} )
to ( 100^{circ} mathrm{C} . ) Then the change in the internal energy of the gas is (Given ( boldsymbol{R}=mathbf{8 . 3 2} boldsymbol{J} boldsymbol{m o l}^{-1} boldsymbol{K}^{-1} mathbf{)} )
A ( .0 .83 times 10^{3} J )
в. ( 4.6 times 10^{3} J )
c ( .2 .08 times 10^{3} J )
D. ( 1.25 times 10^{3} J )
11
234Gas exerts pressure on the walls of
container because the molecules-
A. Are loosing the kinetic energy
B. Are getting stuck to the walls
C. Are transferring their momentum to walls
D. Are accelerated toward walls.
11
235One ( k g ) of diatomic gas is at a pressure
of ( 8 times 10^{4} N / m^{2} . ) The density of the gas
is ( 4 k g / m^{3} . ) What is the energy of the gas due to its thermal motion?
A ( .5 times 10^{4} J )
B . ( 6 times 10^{4} J )
c. ( 7 times 10^{4} J )
D. ( 3 times 10^{4} J )
11
236In a certain gas ( frac{2}{5} ) th of the energy of molecules is associated with the
rotation of molecules and the rest of it
is associated with the motion of the
centre of mass. The average translation energy of one such molecule, when the
temperature is ( 27^{circ} mathrm{C} ) is given by ( x times )
( 10^{-23} J ),then find ( x ? )
A . 62
B. 623
c. 6.21
D. 62.1
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237State whether true or false:
Linear molecules have ( 3 N-5 )
vibrational degrees of freedom, whereas
non linear molecules have ( 3 N-6 )
vibrational degrees of freedom, where ( N ) is no. of atoms present in a molecule.
A. True
B. False
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238Assertion
Mean free path of a gas molecules varies inversely as density of the gas
Reason
Mean free path varies inversely as
pressure of the gas
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 and Reason is correct
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239Root mean square speed of the molecules of ideal gas is ( v ). If pressure
is increased two times at constant
temperature, the ( r m s ) speed will
become:
A ( .2 v )
в. ( frac{v}{2} )
c. ( 4 v )
D.
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240A gas thermometer measures the temperature from the variation of
pressure of a sample of gas. If the pressure measured at the melting point of lead is 2.20 times the pressure
measured at the triple point of water
find the melting point of lead.
( mathbf{A} cdot 600 K )
B. ( 420 K )
( mathbf{c} .790 K )
D. ( 510 K )
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241A gas has a density of 10 particles ( / m^{3} ) and a molecular diameter of ( 0.1 mathrm{m} ). What
is its mean free path?
( mathbf{A} cdot 2.25 m )
в. ( 1 m )
( c .3 m )
D. ( 0.25 m )
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242The internal energy of an ideal gas increases during an isothermal process when the gas is
A. Expanded by adding more molecules to it
B. Expanded by adding more heat to it
c. Expanded against zero pressure
D. Compressed by doing work on it
11
243Boyle’s law holds good for an ideal gas during:
A. Isobaric changes
B. Isothermal changes
c. Isochoric changes
D. Isotopic changes
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244A diatomic gas is filled inside a conducting cylinder. Now we push the piston slowly to make volume of gas
half of initial. Pick correct statements
begin{tabular}{|ccccc|}
hline & & & & \
hline & & & & \
( bullet ) & ( bullet ) & ( bullet ) & ( bullet ) & & \
& ( bullet ) & ( bullet ) & ( bullet ) & & ( bullet ) & ( bullet ) \
( bullet ) & ( bullet ) & ( bullet ) & ( bullet ) & ( bullet ) \
hline
end{tabular}
This question has multiple correct options
A. Pressure of gas Increases because there is more average change in linear momentum of molecule in each collision
B. Pressure force on side wall of container increased
C. Pressure force on piston is increased
D. More molecules collide with piston per unit time
11

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