The ratio of the intensities between two coherent light sources used in Young's double slit experiment is n. Find the ratio of the intensities of principal maximum and minima of the band.

Explanation

Let the intensities of the sources be `I_(1)` and `I_(2)` . According to question `I_(1)=nI_(2)`
Now if `I_("min")` and `I_("min")` be the intensities of central maximum and minima respectively then
`I_("max")/(I_("max"))=(sqrtI_(1)+sqrt(I_(2)))^(2)/(sqrtI_(1)-sqrt(I_(2)))^(2)=(sqrtn.sqrtI_(2)+sqrt(I_(2)))^(2)/(sqrtn.sqrtI_(2)-sqrt(I_(2)))^(2)`
`=(sqrtn+1)^(2)/((sqrtn-1)^(2))=(n+1+2sqrtn)/(n+1-2sqrt(n))`