For what distance is ray optics a good approximation when the aperture is 4 mm wide and the wavelength is 500 nm?

Options

A. 32 m
B. 64 m
C. 16 m
D. 8 m

Answer

A

Explanation

Distance ` = (a^(2))/(lambda) = ((4 xx 10^(-3))^(2))/(500 xx 10^(-9))`
`(16 xx 10^(-6))/(500 xx 10^(-9)) = (160)/(5) = 32` m