Wave Optics

JEE Main level, numerical answer, medium

88 of 191

Question 88 of 191

A fringe width of 6mm6mm was produced for two slits separated by 1mm1mm apart. The screen is placed 10m10m away. The wavelength of light used is xx nmnm. The value of xx to the nearest integer is ______.

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Answer: 600

β=λDd\beta =\dfrac{\lambda D}{d}
λ=βdD\lambda =\dfrac{\beta d}{D}
λ=6×10−3×10−310\lambda =\dfrac{6\times {10}^{-3}\times {10}^{-3}}{10}
λ=6×10−7m=600×10−9m\lambda =6\times {10}^{-7}m=600\times {10}^{-9}m
λ=600nm\lambda =600nm

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