We have compiled the NCERT MCQ Questions for Class 11 Physics Chapter 13 Kinetic Theory with Answers Pdf free download covering the entire syllabus. Practice MCQ Questions for Class 11 Physics with Answers on a daily basis and score well in exams. Refer to the Kinetic Theory Class 11 MCQs Questions with Answers here along with a detailed explanation.
Kinetic Theory Class 11 MCQs Questions with Answers
Multiple Choice Type Questions
Question 1.
Which of the following can be the basis of sesparating a mixture of gases?
(a) Graham’s law of diffusion
(b) Avogadro’s law
(c) Charle’s law
(d) Boyle’s law
Answer
Answer: (a) Graham’s law of diffusion
Question 2.
In the equation, PV = RT, the V refers to the volume of:
(a) 1 g of a gas
(b) 1 mole of a gas
(c) 1 kg of gas
(d) any amount of gas
Answer
Answer: (b) 1 mole of a gas
Question 3.
Gases deviate from perfect gas behaviour because their molecules
(a) are polyatomic
(b) are of very small size
(c) don’t attract each other
(d) interact with each other through intermolecular forces
Answer
Answer: (d) interact with each other through intermolecular forces
Question 4.
Who gave the law of equipartition of energy?
(a) Maxwell
(b) Claussius
(c) Boltzmann
(d) Carnot
Answer
Answer: (a) Maxwell
Question 5.
The law of equipartition of energy is applicable to the system whose constituents are:
(a) in orderly motion
(b) at rest
(c) in random motion
(d) moving with constant speed
Answer
Answer: (c) in random motion
Question 6.
The monoatomic molecules have only three degrees of freedom because they can possess
(a) only translatory motion
(b) only rotatory motion
(c) both translatory and rotatory motion
(d) translatory, rotatory and vibratory motion
Answer
Answer: (a) only translatory motion
Question 7.
A hotter gas implies higher average value of:
(a) heat content
(b) K.E.
(c) total energy
(d) internal energy
Answer
Answer: (b) K.E.
Question 8.
What is the number of degrees of freedom of an ideal diatomic molecule at ordinary temperature?
(a) 3
(b) 5
(c) 7
(d) 6
Answer
Answer: (b) 5
Question 9.
The number of degrees of freedom for translatory motion are
(a) dependent on the nature of translatory motion.
(b) same for all types of molecules.
(c) less for multiatomic molecules.
(d) more for multiatomic molecules.
Answer
Answer: (b) same for all types of molecules.
Question 10.
A man is climbing up a spiral type of staircase. His degrees of freedom are:
(a) 1
(b) 2
(c) 3
(d) more than 3
Answer
Answer: (c) 3
Question 11.
The energy associated with each degree of freedom of a gas molecule is
(a) zero
(b) \(\frac {1}{2}\) kT
(c) kT
(d) \(\frac {3}{2}\) kT
Answer
Answer: (b) \(\frac {1}{2}\) kT
Question 12.
The mean K.E. of a monoatomic gas molecule is
(a) zero
(b) \(\frac {1}{2}\)kT
(c) kT
(d) \(\frac {3}{2}\) kT
Answer
Answer: (d) \(\frac {3}{2}\) kT
Question 13.
Equal volumes of two gases at the same temperature and pressure have the same
(a) number of molecules.
(b) r.m.s. velocity.
(c) no. of molecules with r.m.s. velocities.
(d) none of the above.
Answer
Answer: (a) number of molecules.
Question 14.
The absolute zero is that temperature at which
(а) all molecular linear velocities are zero.
(b) most of the molecular linear velocities are zero.
(c) most of the molecular linear velocities are not zero.
(d) the weight of the gas is zero.
Answer
Answer: (а) all molecular linear velocities are zero.
Question 15.
The speed of sound vs in a gas and rms speed of molecules are related as
(а) \(\frac {v_s}{v_rms}\) = 1
(b) \(\frac {v_s}{v_rms}\) = √γ
(c) \(\frac {v_s}{v_rms}\) = \(\sqrt{\frac {3}{γ}}\)
(d) \(\frac {v_s}{v_rms}\) = \(\sqrt{\frac {γ}{3}}\)
Answer
Answer: (d) \(\frac {v_s}{v_rms}\) = \(\sqrt{\frac {γ}{3}}\)
Question 16.
Which of the following is not a postulate of kinetic theory of gases?
(a) The molecules of a gas are always at rest.
(b) The molecules of a gas are point masses.
(c) The molecules of a gas are perfectly elastic spheres.
(d) The molecules of a gas are identical.
Answer
Answer: (a) The molecules of a gas are always at rest.
Question 17.
The state of greatest potential energy is
(a) gaseous
(b) liquid
(c) solid
(d) solid as well as liquid
Answer
Answer: (a) gaseous
Question 18.
The volume of 5 moles of a gas at N.T.P. in litres is
(a) 112
(b) 11.2
(c) 1.12
(d) 1120
Answer
Answer: (a) 112
Question 19.
If r.m.s. speed of a gas increases, then its pressure :
(a) increases
(b) decreases
(c) remains same
(d) may increase or decrease
Answer
Answer: (a) increases
Question 20.
The pressure P and density p of a gas are related as
(a) P ∝ ρ
(b) P ∝ \(\frac {1}{ρ}\)
(c) P ∝ ρ²
(d) P ∝ \(\frac {1}{ρ^2}\)
Answer
Answer: (a) P ∝ ρ
Question 21.
What happens when the temperature of a gas contained in a vessel is raised?
(a) The molecules of gas move faster and pressure increases.
(b) The molecules of gas move faster and the pressure decreases
(c) The molecules of the gas move slower and the pressure, increases.
(d) The gas molecules move slower and the pressure decreases.
Answer
Answer: (a) The molecules of gas move faster and pressure increases.
Question 22.
For an ideal gas
(a) Size of molecules is negligible.
(b) There is no force of attraction or repulsion amongst the molecules.
(c) It strictly obeys the gas laws.
(d) All of the above.
Answer
Answer: (d) All of the above.
Question 23.
The r.m.s. velocity of a gas is
(a) directly proportional to the density of the gas.
(b) inversely proportional to the density of the gas.
(c) directly proportional to the square of density.
(d) inversely proportional to the square root of the density of the gas.
Answer
Answer: (d) inversely proportional to the square root of the density of the gas.
Question 24.
K.E. of gas molecules is zero at:
(a) 0°C
(b) 273°t
(c) -273°C
(d) none of the above
Answer
Answer: (c) -273°C
Question 25.
In kinetic theory’ of gases, it is assumed that:
(a) the collisions are not perfectly elastic.
(b) the molecular collisions change the density of the gas.
(c) the molecules don’t collide with each other on the well.
(d) between two collisions the molecules travel with uniform velocity.
Answer
Answer: (d) between two collisions the molecules travel with uniform velocity.
Fill in the blanks
Question 1.
The behaviour of real gases approximate to that of perfect gas at low ……………….. and high ………………..
Answer
Answer: pressure, temperature.
Question 2.
Pressure exerted by an ideal gas is numerically equal to \(\frac {2}{3}\)rd of the mean kinetic energy per unit ……………….. of gas
Answer
Answer: volume.
Question 3.
The r.m.s. velocity of molecules at 0°C is doubled at ………………..
Answer
Answer: 819°C.
Question 4.
If the volume of a gas is reduced at constant temperature the frequency of collision ……………….. and mean free path ………………..
Answer
Answer: increases, decreases.
Question 5.
The ……………….. is the measure of average K.E. of the gas.
Answer
Answer: temperature
Question 6.
For a molecule having n degrees of freedom, the energy associated with the molecules is ………………..
Answer
Answer: \(\frac {n}{2}\) kT
Question 7.
The K.E. of a body of mass m is E. The momentum of the body is ………………..
Answer
Answer: \(\sqrt {2mE}\)
Question 8.
One mole of every gas at ……………….. occupies the same volume Le. 22.4 litre.
Answer
Answer: N.T.P
Question 9.
The density of a gas ……………….. during collisions.
Answer
Answer: does not change
Question 10.
The number of molecules with higher most probable speed ……………….. with the rise in temperature.
Answer
Answer: increases
Question 11.
Both STP or NTP refer to a temperature of ……………….. and ……………….. pressure.
Answer
Answer: 0°C or 273 K, 1 atm.
Question 12.
The volume of an ideal gas is ……………….. at absolute zero.
Answer
Answer: zero
Question 13.
Temperature less than absolute zero is ………………..
Answer
Answer: not possible.
Question 14.
Pressure of a gas ……………….. on increase of its temperature.
Answer
Answer: increases
Question 15.
Pressure of a gas ……………….. on decrease of its volume.
Answer
Answer: increases
Question 16.
Pressure of a gas increases on reducing volume due to ………………..
Answer
Answer: increase in the number of collisions per second.
Question 17.
Pressure of a gas increases on increasing its temperature due to ………………..
Answer
Answer: increase in velocity or K.E. of the gas molecules.
Question 18.
All molecular motions stop at ………………..
Answer
Answer: absolute zero
Question 19.
The temperature of a gas ……………….. when it is compressed.
Answer
Answer: increases.
Question 20.
Avogadro number is the number of molecules in ………………..
Answer
Answer: one mole of a gas
Question 21.
The pressure exerted by the molecules of a gas is due to ………………..
Answer
Answer: change in momentum
Question 22.
The perfect or ideal gas is one which obeys ………………..
Answer
Answer: Boyle’s law and Charle’s law.
Question 23.
The relation PV = RT can describe the behaviour of a real gas at ………………..
Answer
Answer: high temperature and low density or low pressure.
Question 24.
The quantity PV/kT represents ………………..
Answer
Answer: number of molecules in the gas.
Question 25.
On increasing the temperature of a gas from 27°C to 927°C, the r.m.s. speed is ………………..
Answer
Answer: doubled.
Question 26.
The air of the atmosphere becomes cold at higher altitude because of ………………..
Answer
Answer: variation in pressure.
Question 27.
A perfect gas is one whose molecules don’t have ……………….. and the ……………….. is negligible as compared to the volume of the gas.
Answer
Answer: molecular attraction, volume of the molecules themselves.
Question 28.
K.E. of 1 mole of a gas is ………………..
Answer
Answer: \(\frac {3}{2}\) RT.
Question 29.
K.E. of 1 molecule of a gas is ………………..
Answer
Answer: \(\frac {3}{2}\) kT.
True/False Type Questions
1. Mark True/False statements
(a) The molecules of an ideal gas are point masses i.e. they are of negligible size.
(b) There is no force of attraction or repulsion amongst the molecules of an ideal gas.
(c) An ideal gas strictly obeys the gas laws.
Answer
Answer:
(a) True
(b) True
(c) True.
2. Mark True/False statements
(a) The intermolecular force for an ideal gas is zero.
(b) The P.E. for the. molecules of an ideal gas is zero.
(c) The total energy of an ideal gas is purely due to kinetic energy of its molecules.
Answer
Answer:
(a) True
(b) True
(c) True.
3. Mark True/False statements
(a) O2, N2, H2 gases are called permanent gases as they obey the gas laws.
(b) Real gases obey gas laws.
(c) The volume of an ideal gas at absolute zero becomes zero.
Answer
Answer:
(a) True
(b) False
(c) True.
4. Mark True/False statements
(a) The molecules of all gases are identical.
(b) The molecules of the gases move randomly in all possible directions with all possible velocities.
(c) The molecules of a gas are perfectly elastic spheres.
Answer
Answer:
(a) False
(b) True
(c) True.
5. Mark True/False statements
(a) The gas molecules move with a constant velocity along a straight line between two successive collisions.
(b) The density of the gas changes due to collisions.
(c) The no. of molecules having speeds tending to zero is very very small.
Answer
Answer:
(a) True
(b) False
(c) True
6. Mark True/False statements
(a) The mean free path of the gas molecules increases with the increase in temperature.
(b) The average K.E. of one gram of all ideal gases at the same temperature is the same.
Answer
Answer:
(a) True
(b) False.
7. Mark True/False statements
(a) The pressure of a gas increases with increase of temperature.
(b) Two different gases at the same temperature have equal root mean square velocities.
Answer
Answer:
(a) True
(b) False
8. Mark True/False statements
(a) The pressure of a gas on the walls of the container increases as its volume is decreased at constant temperature.
(b) Absolute zero degree temperature is not the zero energy temperature.
(c) The mean free path increases with increase in temperature due to the increase in volume at constant pressure.
Answer
Answer:
(a) True
(b) True
(c) True
9. Mark True/False statements
(a) The most probable speed increases with increase in temperature.
(b) The most probable speed is directly proportional to the square root of the absolute temperature.
(c) Absolute temperature can never be negative.
Answer
Answer:
(a) True
(b) True
(c) True
10. Mark True/False statements
(a) The mean free path decreases with the increase in pressure at a constant temperature of the gas.
(b) The temperature of a gas in a container will increase when we put it on a moving train.
(c) Equal volumes of two gases at the same temperature and pressure have the same number of molecules.
Answer
Answer:
(a) True
(b) False
(c) True
Match Type Questions
| Column I | Column II |
| (a) Obeys gas laws | (i) zero |
| (b) Volume of an ideal gas at absolute zero | (ii) K.E. of gas molecules is zero |
| (c) At absolute zero | (iii) point masses |
| (d) Molecules of an ideal gas | (iv) mean free path |
| (e) Distance covered by the molecules between two successive collisions | (v) internal energy of a real gas |
| (f) Depends on volume and temperature | (vi) ideal gas |
| (g) Number of molecules in one mole of a gas | (vii) increases with the increase in temperature |
| (h) Mean free path | (viii) \(\frac {3}{2}\) kT |
| (i) K.E. per mole of a gas | (ix) Avogadro’s number |
| (j) K.E. per molecule of a gas | (x) \(\frac {3}{2}\) RT |
| (k) Does not change during collisions | (xi) density of gas |
Answer
Answer:
| Column I | Column II |
| (a) Obeys gas laws | (vi) ideal gas |
| (b) Volume of an ideal gas at absolute zero | (i) zero |
| (c) At absolute zero | (ii) K.E. of gas molecules is zero |
| (d) Molecules of an ideal gas | (iii) point masses |
| (e) Distance covered by the molecules between two successive collisions | (iv) mean free path |
| (f) Depends on volume and temperature | (v) internal energy of a real gas |
| (g) Number of molecules in one mole of a gas | (ix) Avogadro’s number |
| (h) Mean free path | (vii) increases with the increase in temperature |
| (i) K.E. per mole of a gas | (x) \(\frac {3}{2}\) RT |
| (j) K.E. per molecule of a gas | (viii) \(\frac {3}{2}\) kT |
| (k) Does not change during collisions | (xi) density of gas |
Hope the information shed above regarding NCERT MCQ Questions for Class 11 Physics Chapter 13 Kinetic Theory with Answers Pdf free download has been useful to an extent. If you have any other queries of CBSE Class 11 Physics Kinetic Theory MCQs Multiple Choice Questions with Answers, feel free to reach us so that we can revert back to us at the earliest possible.