Q29. For a two level system, the population of atoms in the upper and lower levels are 3x10* and 0.7x10 3.0x10' m" /W-sand the energy density is 9.0J/m -Hz, the rate of stimulated emission will be (a) 6.3x10' s respectively. If the coefficient of stimulated emission is (b) 4.1x10l6 s- (C) 2.7x10 s (d) 1.8x10' s