Light of wavelength `600 nm` is incident on an aperture of size `2 mm`. Calculate the distance light can travel before its spread is more than the size of aperture.

Options

A. 12.13 m
B. 86.67 m
C. 3.33 m
D. 2.19 m

Answer

B

Explanation

The distance upto which light can travel is
Fresnel distance,
`Z_F = (d^2)/(lambda) = ((2 xx 10^(-3))^2)/(600 xx 10^(-9)) = 6.67 m`