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

1.	The pressure decreases
2.	The pressure increases
3.	The pressure remains the same
4.	The pressure may increase or decrease depending upon the nature of the gas

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 \(PV^{5/3}=\text{constant}.\) During this process, the gas is:

1. Heated

2. Cooled

3. Neither heated nor cooled

4. First heated and then cooled

Which of the following graphs correctly represents the variation of $\beta =-(dV/dP)/V$ with P for an ideal gas at constant temperature ?

(1)

(2)

(3)

(4)