AIIMS 2004
- Exam
- AIIMS
- Year
- 2004
- Subject
- Physics
- Chapter
- Atomic Physics
AIIMS 2004 · Physics · Atomic Physics
Assertion : In He-Ne laser, population inversion takes place...
Assertion : In He-Ne laser, population inversion takes place between energy levels of neon atoms.
Reason : Helium atoms have a meta-stable energy level.
Options
- AIf both assertion and reason are true and reason is the correct explanation of assertion
- BIf both assertion and reason are true but reason is not the correct explanation of assertion
- CIf assertion is true but reason is false
- DIf both assertion and reason are false.
Correct answer
B. If both assertion and reason are true but reason is not the correct explanation of assertion
Step-by-step solution
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 laser. 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.
Sequence of transitions in He-Ne laser. 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.