Q36. a two level system in a thermal (black body) environment can decay from the excited state by both spontaneous and thermally stimulated emission. at room te

Q36. A two level system in a thermal (black body) environment can decay from the excited state by both spontaneous and thermally stimulated emission. At room temperature (300 K), the frequency below which thermal emission dominates over spontaneous emission is nearest to (a) 10 H (b) 10 Hz (c) 10' Hz (d) 10 Hz