Heat is given to an ideal gas in an isothermal process. Then

A. internal energy of the gas will decrease.

B. internal energy of the gas will increase.

C. internal energy of the gas will not change.

D. the gas will do negative work.

A rectangular block of surface area A emits energy E per second at $27^{\circ} \mathrm{C}$. If length and breadth is reduced to half of initial value and temperature is raised to $327^{\circ} \mathrm{C}$ then energy emitted per second becomes

When a diatomic gas (rigid) undergoes adiabatic change, its pressure $(\mathrm{P})$ and temperature $(\mathrm{T})$ are related as $P \propto T^c$. The value of $c$ is

For an ideal gas, the density of the gas is $\rho_0$ when temperature and pressure of the gas are $\mathrm{T}_0$ and $P_0$ respectively. when the temperature of the gas is $2 \mathrm{~T}_0$, its pressure becomes $3 \mathrm{P}_0$. The new density will be