Question

In a Young’* double slit experiment, green light is incident on the two slits. The interference pattern is observed on a screen. Which of the following changes would cause the observed fringes to be more closely spaced ?

(a) Reducing the separation between the slits

(b) Using blue light instead of green light

(c) Used red light instead of green light

(d) Moving the light source further away from the slits

Answer 1

Correct option: (b)

Explanation:

For fringes to be more closely spaced fringe width (β) must be decreased. For this wavelength must decrease.