TEST BANK FOR Quantum Physics 3rd Edition By Stephen Gasiorowicz

1. The energy contained in a volume dV is U(ν,T)dV = U(ν ,T)r2drsinθ dθdϕ when the geometry is that shown in the figure. The energy from this source that emerges through a hole of area dA is dE(ν ,T) = U(ν ,T)dV dAcosθ 4πr2 The total energy emitted is . dE(ν ,T) = dr dθ dϕU(ν,T)sinθ cosθ dA 0 4π 2π ∫ 0 π /2 ∫ 0 cΔt ∫ = dA 4π 2π cΔtU(ν ,T) dθ sinθ cosθ 0 π / 2 ∫ = 1 4 cΔtdAU (ν ,T) By definition of the emissivity, this is equal to EΔtdA ...