Assertion:In He-Ne lase,Population inversion takes place between energy levels of neon atoms.
Reason:Helium atoms have a meta-stable energy level.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are truw but reason is not correct explanation of assertion
C. If assertion is true but reason is false
D. If both assertion and reason are false.

Answer

B

Explanation

Helium-neon laser uses a gaseous mixture of helium and neon.An electric discharge in the gas pumps the helium atoms to higher energy level,(Which is meta stable energy level).Sequence of transitions in He-Ne lase Then these helium atom excite the neon atoms to higher level by collision and produce an inverted population of neon atom which emit radiation when they are stimulated to fall to lower level.