In a double slit experiment, the distance between slits is increased 10 times, whereas their distance from…

In a double slit experiment, the distance between slits is increased 10 times, whereas their distance from screen is halved, the fringe width
  1. remain the same.
  2. becomes $\frac{1}{10}$ times.
  3. becomes $\frac{1}{20}$ times.
  4. becomes $\frac{1}{90}$ times.

Solution

$\begin{aligned} & \text { Fringe width }(\beta)=\frac{D \lambda}{d} \\ & \beta_2=\frac{\frac{D}{2} \lambda}{10 d}=\frac{D \lambda}{20 d} \\ & \beta_2=\frac{\beta_1}{20}\end{aligned}$

Asked in: MHT CET 2024 (16 May Shift 2)

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