Question

The burner on an electric stove has a diameter of .18M, Calculate the rate at which it emits energy if its temperature is 165 C. Assume it had an emissivity of 1.

Answer 1

The radiant energy Q, emitted in a time t by an object that has a Kelvin temperature T, a surface area A, and an emissivity e, is given by,

$Q = e \sigma A T^4 t$

where $\sigma$ is Stefan-Boltzmann's constant with value

5.67 x 10-$J/(s. m². Kº).

Then the rate of emitting energy,

$\frac{dQ}{dt} = e \sigma A T^4$

we have given, e = 1, radius of oven r = 0.09m, T = $165\degree C$ = 438 K, Then Area of the oven

Then rate of energy radiated is ,

$\frac{dQ}{dt} = 53.0045 J/s$