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Question
Laser light of wavelength 630 nm is incident on a pair of slits which are separated by 1.8 mm. If the screen is kept 80 cm away from the two slits, calculate:
1) fringe separation i.e. fringe width.
2) distance of 10th bright fringe from the centre of the interference pattern
Solution
`lambda = 630 nm`
`d = 1.8 xx 10^(-3)`
D = 0.80 m
1) `beta = (lambdaD)/d = (630 xx 10^(-9)xx 0.8)/(1.8 xx 10^(-3) ) = 2.8 xx 10^(-4) m`
2) `x = (nlambdaD)/d = 10 xx 2.8 xx 10^(-4) = 2.8 xx 10^(-3) m`
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