Optics Question 461

Question: Two beams of light having intensities I and 4 I interfere to produce a fringe pattern on a screen. The phase between the beams is π/2 at point A and π at point B. Then, the difference between the resultant intensities at A and B is

Options:

A) 2I

B) 4I

C) 5I

D) 7I

Show Answer

Answer:

Correct Answer: B

Solution:

[b] I(ϕ)=I1+I2+2I1I2cosϕ

Here, I1=I and I2=4I At point A, ϕ=π2

IA=I+4I=5I At point B, ϕ=π

IB=I+4I4I=I

IAIB=4I



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