In a diffraction pattern due to a single slit of width 'a', the first minimum is observed at an angle 30° when light of wavelength 5000 Å is incident on the slit. The first secondary maximum is observed at an angle of:

Options

A. `sin^(-1)(1/4)`
B. `sin^(-1)(2/3)`
C. `sin^(-1)(1/2)`
D. `sin^(-1)(3/4)`

Answer

D

Explanation

For first minima, `sin 30^@ = lambda/a =1/2`
First secondary maxima will be at
`sin theta = (3lambda)/(2a) =3/2 (1/2) implies theta = sin^(-1) (3/4)`