The rate of dissipation of heat by a black body at temperature $T$ is $Q$. What will be the rate of dissipation of heat by another body at temperature $2\,T$ and emissivity $0.25$ ?
The rate of dissipation of heat by a black body at temperature $T$ is $Q$. What will be the rate of dissipation of heat by another body at temperature $2\,T$ and emissivity $0.25$ ?
- A
$16 \,Q$
- B
$4 \,Q$
- C
$8 \,Q$
- D
$4.5 \,Q$
Similar Questions
Six wires each of cross-sectional area $A$ and length $l$ are combined as shown in the figure. The thermal conductivities of copper and iron are $K_1$ and $K_2$ respectively. The equivalent thermal resistance between points $A$ and $C$ is
Six wires each of cross-sectional area $A$ and length $l$ are combined as shown in the figure. The thermal conductivities of copper and iron are $K_1$ and $K_2$ respectively. The equivalent thermal resistance between points $A$ and $C$ is
Liquid cools from $50^oC$ to $45^oC$ in $5$ minutes and from $5^oC$ to $41.5^oC$ in the next $5$ minutes. The temperature of the surrounding is......... $^oC$
Liquid cools from $50^oC$ to $45^oC$ in $5$ minutes and from $5^oC$ to $41.5^oC$ in the next $5$ minutes. The temperature of the surrounding is......... $^oC$
The temperature of a black body reduces to half of its actual value. By what fraction will the amount of radiations given out reduce?
The temperature of a black body reduces to half of its actual value. By what fraction will the amount of radiations given out reduce?
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
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
Star$ S_1$ emits maximum radiation of wavelength $420$ $nm$ and the star $S_2$ emits maximum radiation of wavelength $560 \,\,nm$, what is the ratio of the temperature of $S_1$ and $S_2$ :
Star$ S_1$ emits maximum radiation of wavelength $420$ $nm$ and the star $S_2$ emits maximum radiation of wavelength $560 \,\,nm$, what is the ratio of the temperature of $S_1$ and $S_2$ :