Question

Match List-I with List-II 

List-I	Concept / Device	List-II	Description
A	Optical Pumping	II	Population Inversion
B	He-Ne Laser	I	Four Level Laser
C	Ruby Laser	III	Three Level Laser
D	Optical Resonator	IV	Pair of optically plane parallel mirrors

• A. A-I, B-II, C-III, D-IV
• B. A-II, B-I, C-III, D-IV
• C. A-I, B-II, C-IV, D-III
• D. A-IV, B-III, C-II, D-I

Hint:

Ruby laser is a three-level laser, while He-Ne laser is a four-level laser.

Answer 1

The Correct Option is B

Concept:
Laser action requires population inversion and optical feedback through an optical resonator.

Step 1: Optical pumping.
Optical pumping is used to produce population inversion. \[ A\rightarrow II \]

Step 2: He-Ne laser.
He-Ne laser is a four-level laser system. \[ B\rightarrow I \]

Step 3: Ruby laser.
Ruby laser is a three-level laser system. \[ C\rightarrow III \]

Step 4: Optical resonator.
An optical resonator consists of a pair of optically plane parallel mirrors. \[ D\rightarrow IV \] Therefore: \[ A-II,\ B-I,\ C-III,\ D-IV \] \[ \therefore \text{Correct Answer is (B)} \]