Assignment

A black body which is at a high temperature $T \mathrm{K}$, emitted thermal radiation at the rate of $E \mathrm{Watt} {\mathrm{m}}^{-2}$. The thermal radiation emitted by a body of emissivity equal to $0.5$ at temperature $\frac{T}{4}$ (in $\mathrm{watt}\hspace{0.17em}{\mathrm{m}}^{-2}$) is

Three identical conductors, $P, Q$ and $R$ are symmetrically fixed at point $O$ as shown in figure. The temperature of junction $O$ is

The thermal capacity of $50 \mathrm{g}$ of aluminium is (Specific heat $=0.2 \mathrm{cal} \mathrm{g}°{\mathrm{C}}^{-1}$)

Which of the following instruments can be used to measure the temperature of sun?

When water is heated from $0°\mathrm{C}$ to $10°\mathrm{C}$, then its density

The maximum wavelength of black body emission ${\lambda }_{m^{\text{'}}}$ changes with absolute temperature $T$ of body as

In natural convection, a heated portion of liquid moves because of

Two cylinders of same diameter and length one of iron and other of silver are placed in close contact as shown. If thermal conductivity of silver is $11$ times than that of iron, then temperature of interface A is approximately