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 $\%$)

If the temperature of a black body increases from $7\,^{\circ}C$ to $287\,^{\circ}C$,then the rate of energy radiation increases by

The temperature of a perfect black body is $727^{\circ}C$ and its surface area is $0.1\, m^{2}$. If the Stefan-Boltzmann constant is $\sigma = 5.67 \times 10^{-8} \, W/m^{2} \cdot K^{4}$,then the heat radiated in $1\, min$ is ........ $cal$.

$A$ spherical black body with a radius of $12 \ cm$ radiates $450 \ W$ power at $500 \ K$. If the radius were halved and the temperature doubled,the power radiated in watt would be

The actual temperature of a black body is $727^{\circ}C$. At what temperature in $K$ will the black body emit twice the radiation?

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 . . . . . .