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Kinetic Theory of Gases MCQs: Complete Conceptual Guide with Ideal Gas Laws

The kinetic theory of gases mcqs  forms the microscopic foundation of thermodynamics and explains the macroscopic behavior of gases in terms of molecular motion. Many aspirants find this chapter challenging because it connects abstract assumptions—such as elastic collisions and random molecular motion—to measurable quantities like pressure, temperature, volume, and internal energy. This is precisely why kinetic theory of gases mcqs play a crucial role in exams like NEET, JEE, CUET, state boards, and university entrance tests.

In this chapter, gases are treated as collections of tiny particles obeying well-defined statistical laws. Kinetic theory of gases mcqs concepts such as mean free path, degrees of freedom, average kinetic energy, and Maxwell–Boltzmann distribution emerge naturally from the kinetic model. Understanding how these ideas relate to classical gas laws—Boyle’s law, Charles’ law, and the ideal gas equation—is essential for solving numerical problems and reasoning-based MCQs.

The Kinetic theory of gases MCQs in this section are carefully designed to test not only formula recall but also conceptual clarity. Kinetic theory of gases mcqs questions probe common misconceptions, such as whether molecular motion stops at 0°C, how temperature affects molecular speed, and why gases deviate from ideal behavior at high pressure and low temperature. Several problems also integrate P–V and P–T graphs, which are frequently asked in competitive examinations.

By practicing these kinetic theory of gases MCQs, aspirants develop a deeper understanding of how microscopic molecular behavior governs macroscopic gas properties. This strengthens problem-solving ability, improves accuracy in numerical questions, and builds confidence for physics examinations.

Table of Contents

Why Kinetic Theory of Gases MCQs Are Important

  • They link molecular motion with pressure and temperature

  • They explain internal energy dependence on temperature

  • They test understanding of degrees of freedom

  • They connect ideal gas assumptions with real-world deviations

  • They strengthen interpretation of P–V and P–T graphs

Kinetic Theory of Gases MCQs :

1. According to kinetic theory of gases, consider the statements:

(A) Motion of gas molecules freezes at 0°C
(B) Mean free path decreases if molecular density increases
(C) Mean free path increases if temperature increases at constant pressure
(D) Average kinetic energy per molecule per degree of freedom is 32kT\frac{3}{2}kT for monoatomic gases

Choose the correct option:
a) A and C only
b) B and C only 
c) A and B only
d) C and D only

Answer-b


2. For a perfect gas, two pressures P1P_1 and P2P_2 are shown in the graph. The graph shows:

a) P1>P2P_1 > P_2 
b) P1<P2P_1 < P_2
c) P1=P2P_1 = P_2
d) Insufficient data

Answer-a


3. In kinetic theory of gases, it is assumed that gas molecules:

a) Repel each other
b) Collide elastically 
c) Move with uniform velocity
d) Do not have mass

Answer-b


4. The P–T graph of equal moles of ideal gas of different volumes shows:

a) V1=V2=V3=V4V_1 = V_2 = V_3 = V_4
b) V4>V3>V2>V1V_4 > V_3 > V_2 > V_1
c) V1=V2;  V3=V4V_1 = V_2;\; V_3 = V_4 and V3>V2>V4V_3 > V_2 > V_4 
d) V1>V3;  V3=V2V_1 > V_3;\; V_3 = V_2


5. Coefficient of volume expansion is:

a) Less than linear expansion
b) Twice linear expansion
c) Equal to linear expansion
d) Thrice linear expansion

Answer-d


6. Transmission of pressure equally in a confined liquid is known as:

a) Impulse
b) Conservation of momentum
c) Pascal’s law 
d) Bernoulli’s theorem

Answer-c


7. Correct statements as per kinetic theory:

(i) Temperature measures average kinetic energy
(ii) Temperature depends on nature of gas
(iii) Heavier molecules have lower average speed
(iv) Lighter molecules have lower average speed

a) (i) & (ii)
b) (ii) & (iii)
c) (i) & (iii) 
d) (ii) & (iv)

Answer-c


8. Average thermal energy of a monoatomic gas is:

a) 32kBT\frac{3}{2}k_BT 
b) 52kBT\frac{5}{2}k_BT
c) kBTk_BT
d) 12kBT\frac{1}{2}k_BT

Answer-a


9. All gases deviate from gas laws at:

a) Low pressure, high temperature
b) High pressure, low temperature 
c) Low pressure, low temperature
d) High pressure, high temperature

Answer-b


10. Rotational degrees of freedom of a rigid diatomic molecule:

a) 0
b) 1
c) 2 
d) 3

Answer-c


11. Equal heat supplied to monoatomic and diatomic gases at same temperature:

a) Diatomic gas temperature increases more
b) Monoatomic gas temperature increases more 
c) Both become zero
d) Cannot be determined

Answer-b


12. Gas pressure on container walls is due to molecules:

a) Having finite volume
b) Obeying Boyle’s law
c) Possessing momentum 
d) Colliding with each other

Answer-c


13. Gas molecules behave like:

a) Inelastic spheres
b) Perfectly elastic rigid spheres 
c) Elastic non-rigid spheres
d) Inelastic non-rigid spheres

Answer-b


14. Rise in temperature and pressure depends on:

a) Heat supplied
b) Velocity distribution
c) Gas density
d) All of these

Answer-d


15. NOT an assumption of kinetic theory:

a) Molecules move in straight lines between collisions
b) Molecules are hard spheres of negligible volume
c) Molecules do not collide at all 
d) Collisions are elastic

Answer-c


16. A line parallel to volume axis in P–V diagram is:

a) Isochoric
b) Isobaric 
c) Isothermal
d) None

Answer-b


17. Necessary condition for Boyle’s law:

a) Isothermal 
b) Adiabatic
c) Isobaric
d) Isochoric

Answer-a


18. At constant volume, increase in temperature causes:

a) Fewer collisions
b) More collisions per unit time 
c) Straight-line collisions
d) No change

Answer-b


19. Internal energy of ideal gas depends on:

a) Pressure
b) Volume
c) Temperature only 
d) Pressure and temperature

Answer-c


20. Change in internal energy of real gases:

a) dU=CvdTdU = C_v dT 
b) CpdTC_p dT
c) (Cp−Cv)dT(C_p – C_v)dT
d) RdTRdT

Answer-a


21. Pressure in an accelerating gas-filled compartment is:

a) Same everywhere
b) Lower at front side 
c) Lower at rear
d) Lower at top

Answer-b


22. Volume at 400 mm Hg when 100 cc at 760 mm Hg:

a) 190 cc 
b) 210 cc
c) 150 cc
d) 120 cc

Answer-a


23. Work done by 1.5 moles monoatomic gas heated at constant pressure:

a) 2500 J
b) 1450 J
c) 1245 J 
d) 555 J

Answer-c


24. Internal energy of 2 moles monoatomic gas at 300 K:

a) 7479 J 
b) 6560 J
c) 8120 J
d) 7100 J

Answer-a


25. Volume change from 27°C to −3°C at constant pressure:

a) 300 cm³
b) 270 cm³ 
c) 150 cm³
d) 135 cm³

Answer-b


26. In equation P=ρRT/M0P = \rho RT / M_0, ρ\rho and M0M_0 are:

a) Mass density, mass of gas
b) Number density, molar mass
c) Mass density, molar mass 
d) Number density, mass

Answer-c


27. If P and T double, V halves, number of molecules:

a) Becomes half 
b) Becomes double
c) Becomes four times
d) Remains constant

Answer-a


28. Process AB with same initial and final volume:

a) Work positive
b) Work negative 
c) Temperature increases continuously
d) Isochoric

Answer-b


29. If pressure and volume are halved, temperature:

a) Doubles
b) Becomes one-fourth 
c) Remains constant
d) Is halved

Answer-b

kinetic theory of gases mcqs

Conclusion on Kinetic Theory of Gases MCQs

Mastering kinetic theory of gases MCQs is not just about memorizing formulas—it is about understanding how microscopic molecular motion translates into observable physical behavior. These kinetic theory of gases mcqs  questions challenge aspirants to apply logic, interpret graphs, and connect multiple physical principles within a single problem.

A strong grasp of this chapter helps in later topics such as thermodynamics, heat transfer, and statistical mechanics, making it a foundational unit in physics. Regular practice of concept-driven kinetic theory of gases  MCQs sharpens analytical thinking and reduces errors caused by common misconceptions.

If an aspirant aim to score high in competitive exams, treat kinetic theory of gases MCQs as an opportunity to refine conceptual clarity rather than rote learning. With consistent practice and clear understanding, this chapter becomes one of the most scoring sections in physics.

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