JEE Main 2022 · 27 Jun · Shift 2 · Physics Q38

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PhysicsSingle correct+4 / -1Question 38 of 90

According to kinetic theory of gases,

A. The motion of the gas molecules freezes at 0°C.

B. The mean free path of gas molecules decreases if the density of molecules is increased.

C. The mean free path of gas molecules increases if temperature is increased keeping pressure constant.

D. Average kinetic energy per molecule per degree of freedom is $\frac32k_BT$ (for monoatomic gases).

Choose the most appropriate answer from the options given below:

A and C only

B and C only

A and B only

C and D only

Answer and worked solution

Official answer: B

Check. A is false (motion stops only at absolute zero). B is true ( $\lambda\propto\frac1{nd^2}$ ). C is true (at constant $p$ , $n\propto\frac1T$ ). D is false (it is $\frac12k_BT$ per degree of freedom).

(B)

Topics:Mean free path Degrees of freedom and equipartition

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JEE Main 2022 · 27 Jun · Shift 2, Physics question 38