The pressure and density of a diatomic gas $(\gamma =7/5)$ changes adiabatically from (P, d) to (P', d'). If $\frac{d\text{'}}{d}=32$, then $\frac{P\text{'}}{P}$ should be: 

1.	1/128	2.	32
3.	128	4.	None of the above

Air in a cylinder is suddenly compressed by a piston, which is then maintained at the same position. With the passage of time 

In an adiabatic expansion of a gas, if the initial and final temperatures are \(T_1\) and \(T_2\), respectively, then the change in internal energy of the gas is:
1. \(\frac{nR}{\gamma-1}(T_2-T_1)\)
2. \(\frac{nR}{\gamma-1}(T_1-T_2)\)
3. \(nR ~(T_1-T_2)\)
4. Zero

One mole of helium is adiabatically expanded from its initial state $(P_i,V_i,T_i)$ to its final state $(P_f,V_f,T_f)$. The decrease in the internal energy associated with this expansion is equal to

(1) $C_V(T_i-T_f)$

(2) $C_P(T_i-T_f)$

(3) $\frac{1}{2}(C_P+C_V)(Ti-T_f)$

(4) $(C_P-C_V)(T_i-T_f)$

Unit mass of a liquid with volume V₁ is completely changed into a gas of volume V₂ at a constant external pressure P and temperature T. If the latent heat of evaporation for the given mass is L, then the increase in the internal energy of the system is -

(1) Zero

(2) $P(V_2-V_1)$

(3) $L-P(V_2-V_1)$

(4) L

If the door of a refrigerator is kept open, then which of the following is true ?

1. Room is cooled

2. Room is heated

3. Room is either cooled or heated

4. Room is neither cooled nor heated

In a cyclic process, the internal energy of the gas:

The efficiency of Carnot's engine operating between reservoirs, maintained at temperatures 27°C and –123°C, is 

(1) 50%

(2) 24%

(3) 0.75%

(4) 0.4%

When an ideal gas (γ = 5/3) is heated under constant pressure, then what percentage of given heat energy will be utilised in doing external work ?

1. 40 %

2. 30 %

3. 60 %

4. 20 %

An ideal monoatomic gas expands in such a manner that its pressure and volume can be related by equation $P{V}^{5/3} = cons\tan t$. During this process, the gas is 

(1) Heated

(2) Cooled

(3) Neither heated nor cooled

(4) First heated and then cooled