Question

In young's double slit experiment performed using a monochromatic light of wavelength λ, when a glass plate (μ = 1.5) of thickness xλ is introduced in the path of the one of the interfering beams, the intensity at the position where the central maximum occurred previously remains unchanged. The value of x will be:

(A) 3

(B) 2

(C) 1.5

(D) 0.5

Answer 1

Correct option is (B) 2

Path difference at O = (μ-1)t.

If the intensity at O remains (maximum) unchanged, path difference must be nλ.

⇒ (μ-1)t = nλ

(1.5-1) xλ = nλ

⇒ x = 2n 

For n = 1, x = 2