Physics

Problem

Which of the following expressions gives the total power radiated per unit area

R

by a surface of emissivity

\varepsilon

at absolute temperature

T

? a)

R = \sigma T^{4}

R = \dfrac{\varepsilon\,\sigma T^{4}}{4}

R = \varepsilon\,\sigma T^{4}

R = \varepsilon\,\sigma (T+273)^{4}