When volume changes from $V$ to $2V$ at constant pressure($P$), the change in internal energy will be:
1. $PV$
2. $3PV$
3. $\frac{PV}{\gamma -1}$
4. $\frac{RV}{\gamma -1}$

The initial pressure and volume of a gas are P and V respectively. First, its volume is expanded to 4V by an isothermal process and then compressed adiabatically to volume V. The final pressure will be (γ = 1.5):

One mole of an ideal gas at an initial temperature of $T$ K does $6R$ joules of work adiabatically. If the ratio of specific heats of this gas at constant pressure and at constant volume is $5/3$, the final temperature of the gas will be:
1. $(T-2.4)$ K
2. $(T+4)$ K
3. $(T-4)$ K
4. $(T+2.4)$ K

Which one of the following processes is reversible?

An ideal gas heat engine operates in a Carnot cycle between 227ºC and 127ºC. It absorbs 6 × 10⁴ cals of heat at higher temperatures. The amount of heat converted to work will be?
1. 4.8 × 10⁴ cals
2. 2.4 × 10⁴ cals
3. 1.2 × 10⁴ cals
4. 6 × 10⁴ cals