The temperature of a body is increased from $T_1 = 127^{\circ}C$ to $T_2 = 227^{\circ}C$. The ambient temperature is $T_0 = 27^{\circ}C$. The energies emitted per second by the body at $T_1$ and $T_2$ are $E_1$ and $E_2$ respectively. The ratio of $\frac{E_2}{E_1}$ is:

The temperature at which a black body of unit area loses its energy at the rate of $1 \text{ J/s}$ is:

The rate of dissipation of heat by a black body at temperature $T$ is $Q$. What will be the rate of dissipation of heat by another body at temperature $2T$ and emissivity $0.25$ (in $Q$)?

Assuming the sun to have a spherical outer surface of radius $r$,radiating like a black body at temperature $t^{\circ} C$,the power received by a unit surface (normal to the incident rays) at a distance $R$ from the centre of the sun is,where $\sigma$ is the Stefan's constant.

$A$ small object is placed at the center of a large evacuated hollow spherical container. Assume that the container is maintained at $0 \ K$. At time $t = 0$,the temperature of the object is $200 \ K$. The temperature of the object becomes $100 \ K$ at $t = t_1$ and $50 \ K$ at $t = t_2$. Assume the object and the container to be ideal black bodies. The heat capacity of the object does not depend on temperature. The ratio $(t_2 / t_1)$ is:

If the temperature of a black body is increased from $27^{\circ}C$ to $327^{\circ}C$,the radiation emitted increases by a factor of: