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. `1b lambda+e`
B. `(2b lambda)/(e )`
C. `(2b lambda)/(e ) + e`
D. `(2b lambda)/(e )-e`

Answer

C

Explanation

The direction in which the first minima occurs is `theta` (say). Then, e `sin theta=lambda or e theta=lambda or theta =(lambda)/(e ) " "(because theta," when " theta" small")`
Width of the central maximum `=2b theta+e=(2b lambda)/(e )+e`