Rate of radiation by a black body is 'R' at temperature 'T'. Another body has same area but emissivity is 0.2 and temperature 3T. Its rate of radiation is

A black rectangular surface of area A emits energy E per unit time at $27^\circ$ C. If length and breadth is reduced to $\left(\dfrac{1}{4}\right)^{th}$ of initial value and temperature is raised to $327^\circ$ C, then energy emitted per unit time becomes

The change in internal energy of the mass of gas, when the volume changes from V to 2V at constant pressure P is ($\gamma$ is the ratio of specific heat at constant pressure to that of volume) ($\gamma = \dfrac{C_p}{C_v}$)

An ideal gas expands adiabatically ($\gamma = 1.5$). To reduce the r.m.s. velocity of the molecules 3 times the gas has to be expanded