Question

For laser action to occur, the medium used must have at least three energy levels. What
must be the nature of each of these levels? Why is three the minimum number?

Answer 1

Answer:

A laser produces a beam of light with same frequency and are coherent. Medium plays a very important role for production of Laser . It can be Crystal, Solid,Liquid , Semiconductor or gas can be send to excited state. The material must have controlled purity ,size and shape and must have three energy levels

Explanation:

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