Question

In a double slit-interference experiment the distance between the screen and slits is doubled. The path difference between the rays passing through the two slits and meeting at the position of the central maximum in the screen ???

1)increases

2)decreses

3)remain unchanged

4)may increases or decreases

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Answer 1

we have formula for central maximum for young's double slit experiment

path difference y=distance between scree and slit*wavelength of               light/distance between slits

y=Dw/d

hence when dist between scree and slit is doubled

new path difference y1=2Dw/d

y1=2y

hence it increases by 2 times its original value