Solveeit Logo
Login

Question

Question: For what distance is ray optics a good approximation when the aperture is 4 mm wide and the waveleng...

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

A

22 m

B

32 m

C

42 m

D

52 m

Answer

32 m

Explanation

Solution

Fresnel distance zF=a2λ=(4×10−3)2500×10−9z_{F} = \frac{a^{2}}{\lambda} = \frac{(4 \times 10^{- 3})^{2}}{500 \times 10^{- 9}}

=4×4×10−65×10−7= \frac{4 \times 4 \times 10^{- 6}}{5 \times 10^{- 7}}

∴zF=32m\therefore z_{F} = 32m