A black rectangular surface of area A emits e | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(C) According to the Stefan-Boltzmann law, the power radiated by a black body is given by $P = \sigma A T^4$, where $P$ is the energy emitted per seco

Vedclass · Accepted Answer

$4E$

Vedclass · Answer

(C) According to the Stefan-Boltzmann law, the power radiated by a black body is given by $P = \sigma A T^4$, where $P$ is the energy emitted per second, $\sigma$ is the Stefan-Boltzmann constant, $A$ is the surface area, and $T$ is the absolute temperature in Kelvin.Initial state: $P_1 = E$, $A_1 = A$, $T_1 = 127 + 273 = 400 	ext{ K}$.So, $E = \sigma A (400)^4$.Final state: Length and breadth are halved, so the new area $A_2 = (L/2) 	imes (B/2) = A/4$. The new temperature $T_2 = 527 + 273 = 800 	ext{ K}$.$P_2 = \sigma A_2 T_2^4 = \sigma (A/4) (800)^4$.Taking the ratio: $P_2 / E = [\sigma (A/4) (800)^4] / [\sigma A (400)^4] = (1/4) 	imes (800/400)^4 = (1/4) 	imes (2)^4 = 16/4 = 4$.Therefore, $P_2 = 4E$.

$A$ black rectangular surface of area $A$ emits energy $E$ per second at $127^\circ C$. If length and breadth are reduced to half of their initial values and the temperature is raised to $527^\circ C$, then the energy emitted becomes:

Similar Questions

Two bodies $P$ and $Q$ have thermal emissivities of $\varepsilon_P$ and $\varepsilon_Q$ respectively. Surface areas of these bodies are same and the total radiant power emitted is also at the same rate. If the temperature of $P$ is $\theta_P$ Kelvin,then the temperature of $Q$ i.e.,$\theta_Q$ is:

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

Find the emissive power from the $0.3 \, cm^2$ surface of a tungsten filament bulb at $3000 \, K$ temperature. Take emissivity $e = 0.4$ for the tungsten bulb. (in $, W$)

The energy spectrum of a black body exhibits a maximum around a wavelength $\lambda$. The temperature of a black body is now changed such that the energy is maximum at wavelength $2\lambda/3$. The power radiated by the black body will now increase by a factor of

If the temperature of a perfectly black body is reduced from $T$ to $T/2$,find the percentage decrease in the rate of emission.

Vedclass Test Series

Exam Paper Generator

Online Exam Module