InterviewSolution
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InterviewSolution
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The two slits are 1 mm apart from each other and illuminated with a light of wavelength `5xx10^(-7)` m. If the distance of the screen is 1 m from the slits, then the distance between third dark fringe and fifth bright fringe isA. 1.2 mmB. 0.75 mmC. 1.25 mmD. 0.625 mm |
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Answer» Correct Answer - C Given : `lambda=5xx10^(-7)m, D=1 m, d=1 mm.` Distance of `n^(th)` bright fringe from the centre `= (nD lambda)/(d)` where `n=1,2,3, ……` So the distance fo `5^(th)` bright fringe `= (5D lambda)/(d)` Distance of `n^(th)` dark fringe from the centre `=(n-(1)/(2))(D lambda)/(d)` where `n=1,2,3,4, .........` `3^(rd)` dark fringe `=(3-(1)/(2))(D lambda)/(d)=(5)/(2)(D lambda)/(d)` Distance between them `=(5-(5)/(2))(D lambda)/(d)=(5)/(2)(D lambda)/(d)` `=(5xx1xx5xx10^(-7))/(2xx1xx10^(-3))=12.5xx10^(-4)m=1.25mm.` |
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