A slit 4.0 cm wide is irradiated with microwaves of 2.0 cm. Find the angular spread of central maximum assuming incidence normal to the plane of the slit.

Options

A. `30^(@)`
B. `40^(@)`
C. `45^(@)`
D. `60^(@)`

Answer

D

Explanation

`a = 4 cm = 4 xx 10^(-2)m`
`lambda = 2 cm = 2 xx 10^(-2) m`
Angular spread of central maximum `(2 theta)` is
`a sin theta = lambda n`
`sin theta = (2 xx 10^(2))/(4 xx 10^(-2)) rArr sin theta = (1)/(2) rArr theta = 30^(@)`
Angular spread `= 2 theta = 2 xx 30^(@) = 60^(@)`