posted by BULturp .
Light of wavelength 630 nm passes through a grating and then onto a screen located several meters from the grating. The 1st order bright band is located 0.26m from the central maximum. Light from a second source produces a band 0.21m from the central maximum.
Determine the wavelength of the second source. [Hint: If the angular deflection is small, tan θ = sin θ.]