Answer to Question #280014 in Atomic and Nuclear Physics for BIGIRMANA Elie

Question

Determine approximately the ratio of the probability of spontaneous emission

to the probability of stimulated emission at room temperature in (a) X-ray

region of the EM spectrum (b) the visible region (c) the microwave region.

Answer 1

$u=\frac{8\pi f^2}{c^3}\cdot \frac{hf}{e^{\frac{hf}{kT}-1}},$

$u_1=1.7\cdot 10^{-4},~~\\$

$u_2=5.1\cdot 10^{-5},$

$u_3=2.0\cdot 10^{-7}.$