6.The process of population inversion is to increase the number of atoms in the

7.In Laser beam, the photons are in phase, the resultant intensity is given in terms of amplitude ‘a’ and number of photons ‘n’ is proportional to

8.The number of atoms in the excited state becomes much greater than the number of atoms in the ground state. This is known as

9.Laser can be used in the

10.The life time of atoms in the excited state is normally