Lasers — CSIR Net PYQ (Question 4)

A Lasers previous-year question (PYQ) from Atomic and Molecular Physics (CSIR Net). Read the question, check the correct answer, then practise the full topic.

Question 4 of 14 · 5.0 marks

A two level system in a thermal (black body) environment can decay from the excited state by both spontaneous and thermally stimulated emission. At room temperature ( 300 K ), the frequency below which thermal emission dominates over spontaneous emission is nearest to

1 $10^{13} H z$
2 $10^{8} H z$
3 $10^{5} H z$
4 $10^{11} H z$

Correct answer: Option 1

← Previous Next →

Practise all 14 Lasers questions with instant feedback.

Practise this topic →

About this question

This Lasers PYQ is part of the Atomic and Molecular Physics section of CSIR Net. Browse more Lasers questions or join the PhysicsByAaryan live batch for full conceptual coverage.