Two rods are connected as shown. The rods are of same length and same cross sectional area. In steady state, the  temperature $\left( \theta  \right)$ of the interface will be…….. $^oC$

A black body is heated from $7\,^oC$ to $287\,^oC$. The ratio of radiation emitted is

If the temperature of the sun were to increase from $T$ to $2T$ and its radius from $R$ to $2R$, then the ratio of the radiant energy received on earth to what it was previously, will be

A liquid in a beaker has temperature $\theta \left( t \right)$ at time $t$ and ${\theta _0}$ is temperature of surroundings, then according to Newton's law of cooling the correct graph between loge ${\log _e}(\theta  – {\theta _0})$ and $t$ is

Five wires each of cross-sectional area $A$ and length $l$ are combined as shown. The thermal conductivity of copper and steel are $k_1$ and $k_2$ respectively. The equivalent thermal resistance between $A$ and $C$ is