Question

A parallel beam of monochromatic light of wavelength `5000Å` is incident normally on a single narrow slit of width `0.001mm`. The light is focused by a convex lens on a screen placed on the focal plane. The first minimum will be formed for the angle of diffraction equal to
A. `0^(@)`
B. `15^(@)`
C. `30^(@)`
D. `60^(@)`

Answer 1

Correct Answer - C
`asinthetan=nlamda`
`:.sintheta=(1xx5xx10^(-7))/(10^(-6))=(1)/(2)" ":.theta=30^(@)`