In a single slit diffraction of light of wavelength `lambda` by a slit of width e, the size of the central maximum on a screen at a distance b is

Options

A. (a) `2blambda+e`
B. (b) `(2blambda)/(e)`
C. (c) `(2blambda)/(e)=e`
D. (d) `(2blambda)/(e)-e`

Answer

C

Explanation

The direction in which the first minima occurs is `theta` (say). Then `e sin thetalambda` or `etheta=lambda` or, `theta=lambda/e`
(`:' theta=sin theta` when `theta` small)

Width of the central maximum `=2b theta+e=2b*lambda/e+e`