physics
posted by jibjab on .
When light of wavelength 495 nm passes through a single slit of unknown width, the diffraction pattern displays a fourthorder maximum where the third minimum of light of an unknown wavelength had been observed to fall. What is the unknown wavelength?

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.
http://www.walterfendt.de/ph14e/singleslit.htm