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Estimate how large can be the aperture o...

Estimate how large can be the aperture opening to work with laws of ray optics using a monochromatic light of wavelength 450 nm, to a distance of around 20 m.

A

6 mm

B

3 mm

C

2 mm

D

8 mm

Text Solution

Verified by Experts

The correct Answer is:
B
Now, here we are given Fresnel distance equal to 20 m `lambda=450` nm we have to estimate value of a
Putting `Z_(F)=a^(2)/lambda,a=sqrt(Z_(F)lambda)=3xx10^(-3)m or 3mm`
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