Question

What is the need to achieve population inversion?

(a) To excite most of the atoms

(b) To bring most of the atoms to ground state

(c) To achieve stable condition

(d) To reduce the time of production of laser

The question was posed to me in an international level competition.

This interesting question is from Laser in division Laser of Engineering Physics II

Answer 1

Right answer is (a) To excite most of the atoms

To elaborate: When population inversion is achieved, the majority of atoms are in the excited state. This causes amplification of the incident beam by stimulated emission. Thus the laser beam is produced.