Optics Question 468

Question: A plane wave front (λ=6×107m) falls on a slit 0.4 mm wide. A convex lens of focal length 0.8 m placed behind the slit focusses the light on a screen. What is the linear diameter of second maximum?

Options:

A) 6 mm

B) 12 mm

C) 3 mm

D) 9 mm

Show Answer

Answer:

Correct Answer: A

Solution:

[a] For secondary maxima d sinθ=5λ2

dθ=d.xD(f)=5λ2

2x=5λfd=5×0.8×1074×104=6×103m=6mm



NCERT Chapter Video Solution

Dual Pane