## Kinetic Theory Questions and Answers Part-20

1. One mole of monoatomic gas and three moles of diatomic gas are put together in a container. The molar specific heat $\left( J K^{-1}mol ^{-1}\right)$   at constant volume is $\left(R=8.3 J K^{-1}mol ^{-1}\right)$
a) 18.7
b) 18.9
c) 19.2
d) None of the above

Explanation: 2. The temperature of argon, kept in a vessel, is raised by $1 ^{\circ}C$ at a constant volume. The total heat supplied to the gas is a combination of translational and rotational energies. Their respective shares are
a) 60% and 40%
b) 40% and 60%
c) 50% and 50%
d) 100% and 0%

Explanation: 100% and 0%

3. On giving equal amount of heat at constant volume to 1 mol of a monoatomic and a diatomic gas the rise in temperature $\left(\triangle T\right)$ is more for
a) Monoatomic
b) Diatomic
c) Same for both
d) Can not be predicted

Explanation: Monoatomic

4. The kinetic energy, due to translational motion, of most of the molecules of an ideal gas at absolute temperature T is
a) kT
b) k/T
c) T/k
d) 1/kT

Explanation: kT

5. The number of translational degrees of freedom for a diatomic gas is
a) 2
b) 3
c) 5
d) 6

Explanation: The number of translational degrees of freedom for a diatomic gas is 3

6. The value of the gas constant (R) calculated from the perfect gas equation is 8.32 joules/gm mole K, whereas its value calculated from the knowledge of $C_{P}$  and $C_{v}$  of the gas is 1.98 cal/gm mole K. From this data, the value of J is
a) 4.16 J / cal
b) 4.18 J / cal
c) 4.20 J / cal
d) 4.22 J / cal

Explanation: 4.20 J / cal

7. For a gas if ratio of specific heats at constant pressure and volume is $\gamma$ then value of degrees of freedom is
a) $\frac{3\gamma-1}{2\gamma-1}$
b) $\frac{2}{\gamma-1}$
c) $\frac{9}{2}{\gamma-1}$
d)$\frac{25}{2}{\gamma-1}$

Explanation: For a gas if ratio of specific heats at constant pressure and volume is $\gamma$ then value of degrees of freedom is $\frac{2}{\gamma-1}$

8. The ratio of specific heat of a mixture of one mole of helium and one mole of hydrogen gas will be
a) 1
b) 1.5
c) 1.53
d) 1.33

Explanation: The ratio of specific heat of a mixture of one mole of helium and one mole of hydrogen gas will be 1.5

9. For a gas $\gamma=7\diagup5$  . The gas may probably be
a) Helium
b) Hydrogen
c) Argon
d) Neon

Explanation: For a gas $\gamma=7\diagup5$  . The gas may probably be Hydrogen
a) $\frac{1+n}{2}$
b) $1+\frac{1}{n}$
c) $1+\frac{n}{2}$
d) $1+\frac{2}{n}$
Explanation: If a gas has n degrees of freedom ratio of specific heats of gas is $1+\frac{2}{n}$