During thermodynamic process, the increase in internal energy of a system is equal to the $\mathrm{w}_{0 r k}$ done on the system. Which process does the system undergo?

How much should the pressure be increased in order to reduce the volume of a given mass of gas by $5 \%$ at the constant temperature?

A polyatomic gas is compressed to $\left(\frac{1}{8}\right)^{\text {th }}$ of its volume adiabatically. If its initial pressure is $\mathrm{P}_0$, its new pressure will be [Given, $\frac{\mathrm{C}_{\mathrm{p}}}{\mathrm{C}_{\mathrm{v}}}=\frac{4}{3}$ ]

The pressure ' P ', volume ' V ' and temperature ' T ' of a gas in a jar ' $A$ ' and the gas in other jar ' $B$ ' is at pressure ' 2 P ', volume ' V ' and temperature ' $\frac{T}{4}$ '. Then the ratio of the number of molecules in jar A and jar B will be