Question

In Young's double-slit experiment, the fringe width is 0.6 mm. If the distance between the slits and screen is doubled, and the separation between slits is halved, the new fringe width will be:

• A. 0.3 mm
• B. 1.2 mm
• C. 2.4 mm
• D. 4.8 mm

Hint:

Fringe width increases with screen distance and decreases with slit separation.

Answer 1

The Correct Option is C

Fringe width, \[ \beta \propto \frac{D}{d} \] Doubling \(D\) and halving \(d\) increases \(\beta\) by factor 4. \[ \beta' = 4 \times 0.6 = 2.4\ \text{mm} \]