$A$ 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

$Assertion :$ Bodies radiate heat at all temperatures.
$Reason :$ Rate of radiation of heat is proportional to the fourth power of absolute temperature.

$A$ black rectangular surface of area $A$ emits energy $E$ per second at $27^{\circ} C$. If length and breadth are reduced to $1/3$ of their initial values and the temperature is raised to $327^{\circ} C$,then the energy emitted per second becomes:

The temperature of a body is increased from $T_1 = 127^{\circ}C$ to $T_2 = 227^{\circ}C$. The ambient temperature is $T_0 = 27^{\circ}C$. The energies emitted per second by the body at $T_1$ and $T_2$ are $E_1$ and $E_2$ respectively. The ratio of $\frac{E_2}{E_1}$ is:

The rectangular surface of area $8 \text{ cm} \times 4 \text{ cm}$ of a black body at a temperature of $127^{\circ}\text{C}$ emits energy at the rate of $E$ per second. If the length and breadth of the surface are each reduced to half of the initial value and the temperature is raised to $327^{\circ}\text{C}$,the rate of emission of energy will become

Two identical bodies have temperatures $277^{\circ} C$ and $67^{\circ} C$. If the surroundings temperature is $27^{\circ} C$, the ratio of loss of heats of the two bodies during the same interval of time is (approximately) (in $ : 1$)