When light of wavelength 495 nm passes through a single slit of unknown width, the diffraction pattern displays a fourth-order maximum where the third minimum of light of an unknown wavelength had been observed to fall. What is the unknown wavelength?

Answer 1

consider the maximum

width*sinTheta=(4+.5)495nm (appx)
and the minium of
wideth*sinTeta=4lambda

since the angles are the same, then
4lambda=4.5*495nm
solve for lambda.
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