On a clear sunny day,an object at temperature $T$ is placed on the top of a high mountain. An identical object at the same temperature is placed at the foot of the mountain. If both the objects are exposed to sun-rays for two hours in an identical manner,the object at the top of the mountain will register a temperature

Determine whether the following statements are True or False:
$(a)$ "Conduction stops once a rod achieves thermal steady state."
$(b)$ $A$ surface that is a good emitter is also a good absorber.
$(c)$ $A$ perfect black body must be black in color.
$(d)$ The value of heat capacity is the same under different conditions for a given matter.

The sun,acting as a black body,emits maximum radiation at a wavelength of $0.48 \ \mu m$. The average radius of the sun is $6.96 \times 10^{8} \ m$. The Stefan-Boltzmann constant is $5.67 \times 10^{-8} \ W/m^2K^4$ and Wien's constant is $0.293 \ cm \cdot K$. The decrease in the mass of the sun per second due to radiation is ..... $kg/s$.

In the variable state,the rate of flow of heat is controlled by

The dimensions of $\sigma b^4$, where $\sigma$ is Stefan's constant and $b$ is Wien's constant, are:

Two bodies $A$ and $B$ have thermal emissivities of $0.01$ and $0.81$ respectively. The outer surface areas of the two bodies are the same. The two bodies emit total radiant power at the same rate. The wavelength ${\lambda _B}$ corresponding to maximum spectral radiancy in the radiation from $B$ is shifted from the wavelength corresponding to maximum spectral radiancy in the radiation from $A$ by $1.00\;\mu m$. If the temperature of $A$ is $5802\;K$,then: