Question

2 sources having intensity in the ratio 81/1 produce interference. Find the ratio of maximum to minimum intensity.

Answer 1

Let I1 and I2 be the given intensity first source and second source respectively..

Given , I1 / I2 = 81/1

For maximum and minimum intensity, using formula:
I (max.) = (√I1 + √I2)²
= (√81 + √1)²
= (9+1)²
= (10)²
= 100

I (min.) = ( √I1 - √I2)²
= (√81 - √1)²
= (9-1)²
= (8)²
= 64

Hence ratio of maximum to the minimum intensity is:

I(max.) / I(min.) = 100 / 64
= 25 / 16



Hope it helps....☺