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Interference frings of yellow light of wavelength 6000 A are formed by Billet split lenses. The distance from source to lens is 24 cms. The focal length of lens is 15 cm The lens halves are separated by `0.06` mm. The distance of source to screen is 200 cms. Calculate the fringe width (in mm) Round off the answer to nearest integer. |
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Answer» Correct Answer - `5 mm` `u=-24` `v=(uf)/(u+f)` `v=(-24xx15)/(-24+15)=(124xx15)/8=40` `Rightarrow D=200-24-40=136` cm `(R_(1))/(-0.03)=v/u=40/(-24)` `R_(1)=40/24xx0.03=0.05` mm `Rightarrow d=0.05xx2+0.06=0.16xx10^(-3)`m `beta=(lamdaD)/d=(6000xx10^(-10)xx136xx10^(-2))/(0.16xx10^(-3))` `beta=51xx10^(-4)m=5.1` mm |
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