2. Light of wavelength 600 nm is incident normally on a plane diffraction grating G. Using a spectrometer telescope, first order maxima are observed at A and B at angles of 86.67° and 116.67°. (N.B. 60' = 1°) the 86°40' 116°40' Calculate a) the number of lines per mm of the grating b) the number of diffraction maxima seen (including the zero order)

2. Light of wavelength 600 nm is incident normally on a plane diffraction grating G. Using a spectrometer telescope, first order maxima are observed at A and B at angles of 86.67° and 116.67°. (N.B. 60' = 1°) the 86°40' 116°40' Calculate a) the number of lines per mm of the grating b) the number of diffraction maxima seen (including the zero order)