Assertion and Reason Questions for Class 11 Physics Chapter 13 Kinetic Theory
Directions: Choose the correct option from the following:
(a) Both A and R are true and R is the correct explanation of A
(b) Both A and R are true but R is NOT the correct explanation of A
(c) A is true but R is false
(d) A is false and R is also false
Q.1. Assertion (A) : The number of degrees of freedom of a linear triatomic molecules is 7.
Reason (R) : The number of degree of freedom depends on number of particle in the system.
Answer
Answer: (b)Q.2. Assertion (A) : Absolute zero is not the temperature corresponding to zero energy.
Reason (R) : The temperature at which no molecular motion ceases is called absolute zero
temperature.
Answer
Answer: (a)Q.3. Assertion (A) : The ratio of specific heat of a gas at constant pressure and specific heat at constant volume for a diatomic gas is more than that for a monatomic gas.
Reason (R) : The molecules of a monatomic gas have more degree of freedom than those of a diatomic gas.
Answer
Answer: (d)Q.4. Assertion (A) : An undamped spring-mass system is simplest free vibration system.
Reason (R) : It has three degrees of freedom.
Answer
Answer: (c)Q.5. Assertion (A) : Air pressure in a car tyre increases during driving.
Reason (R) : Absolute zero degree temperature is not zero energy temperature.
Answer
Answer: (b)Q.6. Assertion (A) : Specific heat of a gas at constant pressure is greater than its specific heat at constant volume.
Reason (R) : At constant pressure, some heat is spent in expansion of the gas.
Answer
Answer: (a)Q.7. Assertion (A) : 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 (R) : The molecules of a gas collide with each other and the velocities of the molecules
change due to collision.
Answer
Answer: (b)Q.8. Assertion (A) : Mean free path of gas molecules varies inversely as density of the gas.
Reason (R) : Mean free path of gas molecules is defined as the average distance travelled by a molecule between two successive collisions.
Answer
Answer: (b)Q.9. Assertion (A) : The root mean square velocity of molecules of a gas having Maxwellian distribution of velocities is higher than their most probable velocity, at any temperature.
Reason (R) : A very small number of molecules of a gas molecules which posses very large velocities.
Answer
Answer: (c)Q.10. Assertion (A) : Vibrational energy of diatomic molecule corresponding to each degree of freedom is kBT.
Reason (R) : For every molecule, vibrational degree of freedom is 2.