If a black body at 400 K surrounded by atmosphere at 300 K has rate of cooling ' $\mathrm{R}_0$ ', the same body at 900 K , surrounded by same atmosphere, will have rate of cooling nearly

The temperature of an ideal gas is increased from 100 K to 400 K . If ' $x$ ' is the R.M.S. velocity of its molecules at 100 K , it becomes

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