Question

If two light waves having same frequency have intensity ratio 4 : 1 and they interfere, the ratio of maximum to minimum intensity in the pattern will be(a) 9 : 1(b) 3 : 1
(c) 25 : 9(d) 16 : 25

Answer 1

a. 9:1 should be the correct answer

Answer 2

Answer:

(a) 9 : 1

Explanation:

Intensity ratio = 4 : 1 (Given)

Width is directly proportional to the intensity and intensity is directly proportional to the square of the amplitude.

Thus,

I ∝ a^2

I1/I2 = (a1/a2)²

4/1 = (a1/a2)²

a1/a2 = 2

a1 = 2a2

Ratio of maximum to minimum intensity by -

Imax / Imin = (a1+a2)² / (a1-a2)²

Imax / Imin = (2a2+a2)² / (2a2-a2)²

Imax / Imin = 3² / 1²

Imax / Imin = 9 / 1

Therefore, ratio of maximum to minimum intensity is 9:1.