Light with an average flux of $20 \mathrm{~W} / \mathrm{cm}^2$ falls on a non-reflecting surface at

Question

Light with an average flux of $20 \mathrm{~W} / \mathrm{cm}^2$ falls on a non-reflecting surface at momal incidence having surface area $20 \mathrm{~cm}^2$. The energy received by the surface during time span of 1 minutes is

Professor PC Thomas Classes · Answer

Energy $= 	ext{Flux} 	imes 	ext{Area} 	imes 	ext{Time} = 20 	imes 20 	imes 60 = 24000 	ext{ J} = 24 	imes 10^3 	ext{ J}$.