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Question Bank No: 2

1. The molar heat capacity in a process of diatomic gas. If it does a work of Q/4 when heat Q is supplied to it is

a)		$\frac{2}{5} R$
b)		$\frac{10}{3} R$
c)		$\frac{5}{3} R$
d)		$\frac{6}{5} R$

2. If pressure and temperature of an ideal gas are doubled and volume is halved, the number of molecules of the gas

a)		Become half
b)		Become two times
c)		Become 4 times
d)		Remain constant

3. PV diagram of a diatomic gas is a straight line passing through origin. The molar heat capacity of the gas in the process will be

a)		4R
b)		3R
c)		4R/3
d)		2.5 R

4. At absolute zero

a)		All substances exist in solid form
b)		Molecular motion ceases
c)		Water becomes ice
d)		None of these

5. Two spheres of the same material have radii 1m and 4m and temperatures 4000 K and 2000 K respectively. The ratio of the energy radiated per second by the first sphere to that by the second is

a)		1 : 1
b)		16 : 1
c)		4 : 1
d)		1 : 9

6. In a given process on an ideal gas, dW = 0 and dQ < 0 then for the gas

a)		The temperature will decreases
b)		The volume will increase
c)		The pressure will remain constant
d)		The temperature will increase

7. The heat given to an ideal gas in isothermal condition is used

a)		in rising temperature
b)		in doing external work
c)		in rising temperature and doing external work
d)		in increasing internal energy

8. If one mole of mono atomic gas (r = 5/3) is mixed with one mole of a diatomic gas (r = 7/3), the value of r for the mixture is

a)		1.4
b)		1.5
c)		1.53
d)		3.07

9. A mono atomic gas (r = 5/3) is suddenly compressed to $\frac{1}{8} th$ of its volume adiabatically, then the pressure of the gas will change to

a)		24/5
b)		8
c)		40/3
d)		32

10. For an adiabatic expansion of a perfect gas the value of $\frac{Δ ρ}{ρ}$ is equal to

a)		$γ \frac{Δ ρ}{V}$
b)		$- γ \frac{Δ ρ}{V}$
c)		$- γ \frac{Δ V}{V}$
d)		$- γ^{2} \frac{Δ V}{V}$

11. A wall has two layers A and B each made off different materials. Both layers are of same thickness. But the thermal conductivity of A is twice that of B. If in the steady state, the temperature differences across the wall is $24^{0} C$ , then the temperature difference across the layer B is

a)		$8^{0} C$
b)		$12^{0} C$
c)		$16^{0} C$
d)		$20^{0} C$

12. Illuminance of a surface is measured in

a)		Lumen
b)		Candela
c)		lux $m^{- 2}$
d)		lux

13. Which of the following will not have have the dimensions of potential energy?

a)		Torque x angular displacement
b)		Rotational inertia x ${(angular frequency)}^{2}$
c)		Position Vector x momentum
d)		Displacement x momentum

14. International unit of temperature is

a)		Degree Celsius
b)		Degree Fahrenheit
c)		Kelvin
d)		Both (a) and (b