Discussion Forum



1)

 A light wave of wavelength  $\lambda$  is incident on a slit of width d. The resulting diffraction pattern is observed on a screen at a distance of D. If the linear width  of the principal  maxima is equal to the width  of the slit, then the distance D is 


A) $\frac{2\lambda}{d}$

B) $\frac{d^{2}}{2\lambda}$

C) $\frac{2\lambda^{2}}{d}$

D) $\frac{d^{}}{\lambda}$

Answer:

Option B

Explanation:

 The linear width of the principal maxima,

$\beta=\frac{2D\lambda}{d}$

 It is given that, the linear width of the principal maxima is equal to the width of the slit.

$\therefore$     $d=\frac{2D\lambda}{d}\Rightarrow D=\frac{d^{2}}{2\lambda}$