If the intensity ratio of two coherent sources used in Young's double slit experiment is `49 : 1`, then the ratio between the maximum and minimum intensities in the interference pattern is

Options

A. `a)1:9`
B. b)`9:16`
C. `c)25:16`
D. `d)16:9`

Answer

D

Explanation

Given, `(l_1)/(l_2) = (49)/(1)`
We know the condition maximum and minimum
`(I_("max"))/(I_("min")) = ((sqrt(l_1 ) + sqrt(l_2) //2)^2)/( (sqrt(l_1 )- sqrt(l_2) //2 )^2`
Here, `(sqrt(l_1))/(sqrt(l_2))= (7)/(1)`
`(sqrt(l) + sqrt(l_2) )/( sqrt(l_2) - sqrt(l_1) )= (7+1)/(7-1) = (8)/(6)`
Hence, `(I_("max"))/(I_("min")) = ((4)/(3))^2 = (16)/(9)`