Suppose that one of the slit in Young's experiment is wider than the order, so the amplitude of the light reaching the central part of the screen from one slit, acting alone, is twice that from the other slit, acting alone. Obtain an expression for the light intensity I at the screen as a function or `theta` the angular position.

Explanation

We know that
`I=a_(1)^(2) + a_(2)^(2) + 2a_(1)a_(2) = (a_(1)+a_(2))^(2) = 9a^(2)`
.At central point `delta`=0, if `l_(0)` be the intensity, then
`therefore a^(2)=(I_(0)//9)`