Question

Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is 25. The intensities of the sources are in the ratio
(a) 25 : 1(b) 5 : 1(c) 9 : 4(d) 25 : 16​

Answer 1

answer is in attachment

thank you

option c is correct

Answer 2

Let Maximum intensity be I .

Let Minimum intensity be i .

Let the original intensities be I₁ and I₂ .

I : i = ( √I₁ + √I₂ )² : ( √I₁ - √I₂ )²

= > 5 : 1 = √I₁ + √I₂ : √I₁ - √I₂

By componendo and dividendo :

= > ( 5 + 1 )/( 5 - 1 ) = 2 √I₁ : 2 √I₂

= > 6 / 4 = √I₁ : √I₂

= > √I₁ : √I₂ = 3 / 2

Square both sides :

= > I₁ : I₂ = 36/16

= > I₁ : I₂ = 9 : 4

ANSWER :

OPTION C