-->

Wave Optics

Question
CBSEENPH12040158

The maximum numbers of possible interference maxima for slit separation equal to twice the wavelength in Young's double slit experiment is

  • infinite

  • five

  • three

  • zero

Solution

B.

five

The condition of interference maxima is

d sin θ = sin θ  = dGiven, d = 2λsin θ = 2λ = n/2

The magnitude of sin θ lies between 0 and 1

When n = 0, sinθ = 0 ⇒θ = 0°

When n = 1, sin θ = 1/2 ⇒ θ =30°

When n = 2, sin θ = 1⇒ θ =90°

Thus, there is central maximum ( θ = 0°), on other side of it maxima lie at θ = 30° and θ = 90°, so maximum number of possible interference maxima is 5.