In young's double slit experiment, if the separation between coherent sources is halved and the distance of the screen

In young's double slit experiment if the separation between coherent sources is halved and the distance  of the screen form the coherent sources is doubled then the fringe width becomes:(1) one-fourth(2) double(3) half(4) four times

Correct answer is  (4) four times Fringe with becomes 4 times

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