Two black spheres $P$ and $Q$ have radii in the ratio $4:3$. The wavelengths of maximum intensity of radiation are in the ratio $4:5$ respectively. The ratio of radiated power by $P$ to $Q$ is

Two spherical bodies of radii $r_1$ and $r_2$ have surface temperatures $T_1$ and $T_2$ respectively. They radiate the same power. The ratio $r_1/r_2$ is . . . . . .

The spectral energy distribution of a star is maximum at a temperature twice that of the Sun. The total energy radiated by the star is

Two bodies $A$ and $B$ at temperatures $T_1 \ K$ and $T_2 \ K$ respectively have the same dimensions. Their emissivities are in the ratio $1: 3$. If they radiate the same amount of heat per unit area per unit time,then the ratio of their temperatures $(T_1: T_2)$ is

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

If the temperature of the sun is decreased by $1 \%$,then the value of the solar constant will change by ........... $\%$