The interference pattern is obtained with two coherent light sources of intensity ratio 9: 1 . The ratio of I_ MAX +I_ MIN I_ MAX -I_ MIN is . The values of and are:

Step-by-step solution

Let the intensities of the two coherent sources be I₁ and I₂ . Given the ratio I₁ : I₂ = 9 : 1 , we can write I₁ = 9k and I₂ = k for some constant k . The amplitudes a₁ and a₂ are proportional to the square root of the intensities, so a₁ = 9k = 3 k and a₂ = k . The maximum intensity I_ MAX and minimum intensity I_ MIN in an interference pattern are given by I_ MAX = ( I₁ + I₂ )^2 and I_ MIN = ( I₁ - I₂ )^2 . Substituting the values, I_ MAX = (3 k + k )^2 = (4 k )^2 = 16k and I_ MIN = (3 k - k )^2 = (2 k )^2 = 4k .