An ideal gas $(\gamma = 1.5)$ is expanded adiabatically. To reduce the root mean square velocity of molecules two times, the gas should be expanded (in $\times$)

An ideal gas,undergoing adiabatic change,has which of the following pressure-temperature relationships?

$A$ rigid diatomic gas undergoes adiabatic change. Its pressure $P$ and temperature $T$ are related as $P \propto T^x$ where $x$ is (in $.5$)

Given below are two statements:
Statement-$I$: When $\mu$ amount of an ideal gas undergoes adiabatic change from state $(P_1, V_1, T_1)$ to state $(P_2, V_2, T_2)$,the work done is $W = \frac{\mu R(T_2 - T_1)}{1 - \gamma}$,where $\gamma = \frac{C_P}{C_V}$ and $R$ is the universal gas constant.
Statement-$II$: In the above case,when work is done on the gas,the temperature of the gas would rise.
Choose the correct answer from the options given below:

$A$ gas is being compressed adiabatically. The specific heat of the gas during compression is

$A$ vessel contains $0.15 \ \text{m}^3$ of a gas at pressure $8 \ \text{bar}$ and temperature $140^\circ \text{C}$ with $c_p = 3R$ and $c_v = 2R$. It is expanded adiabatically until the pressure falls to $1 \ \text{bar}$. The work done during this process is . . . . . . $\text{kJ}$.