$A$ black body radiates energy at a rate of $E \, W/m^2$ at a temperature of $T \, K$. When the temperature is reduced to $T/2 \, K$,the radiated energy will be .....

The heat radiated per unit area in $1\,hour$ by a furnace whose temperature is $3000\,K$ is $(\sigma = 5.7 \times 10^{-8}\,W\,m^{-2}\,K^{-4})$.

Three large identical plates are kept parallel to each other. The outer two plates are maintained at temperatures $T$ and $2T$, respectively. The temperature of the middle plate in steady state will be close to ........... $T$.

The temperatures of two bodies $A$ and $B$ are $727^{\circ}C$ and $127^{\circ}C$. The ratio of the rate of emission of radiations will be:

Three very large plates of same area are kept parallel and close to each other. They are considered as ideal black surfaces and have very high thermal conductivity. First and third plates are maintained at absolute temperatures $2 T$ and $3 T$ respectively. Temperature of the middle plate in steady state is

Two identical metal balls at temperatures $200^{\circ}C$ and $400^{\circ}C$ are kept in air at $27^{\circ}C$. The ratio of net heat loss by these bodies is: