In a double slit experiment, instead of taking slits of equal widths, one slit is made twice as wide as the other. Then, in the interference pattern

Options

A. the intensities of both the maxima and the minima increases
B. the intensity of the maxima increases and the minima has zero intensity
C. the intensity of maxima decreases and that of minima increases
D. the intensity of maxima decreases and the minima has zero intensity

Answer

A

Explanation

In interference we know that `I_(max) = (sqrt(I_(1)) + sqrt(I_(2)))^(2)` and `I_(min) = (sqrt(I_(1)) - sqrt(I_(2)))^(2)`
Under normal conditions (when the widths of both the slits are equal)
`I_(1) = I_(2) = I (say) , I_(max) = 4I and I_(min) = 0`
When the width of one of the slits is increased. Intensity due to that slit would increases, while that of the other will remain smae. So let : `I_(1) = I and I_(2) = eta I (eta gt 1)`
Then, `I_(max) = I (1+ sqrt(eta))^(2) gt 4 I` and `I_(min) = I(sqrt(eta) - 1)^(2) gt 0`
Intnsity of both maxima and minima is increased.