If the temperature of a hot body is increased by $50 \%$,then the increase in the quantity of emitted heat radiation will be approximately (in $\%$)

Write the value and dimensional formula of the Stefan-Boltzmann 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:

Which of the following graphs correctly represents the relation between $\ln E$ and $\ln T$, where $E$ is the amount of radiation emitted per unit time from unit area of a body and $T$ is the absolute temperature?

$Assertion :$ Bodies radiate heat at all temperatures.
$Reason :$ Rate of radiation of heat is proportional to the fourth power of absolute temperature.

$A$ black rectangular surface of area $A$ emits energy $E$ per second at $27^{\circ} C$. If length and breadth are reduced to $1/3$ of their initial values and the temperature is raised to $327^{\circ} C$,then the energy emitted per second becomes: