A silt of width a is illuminated bymonochromatic light of wavelength 650nm at normal incidence. Calculate the value of a , when
(a) the first minimum falls at an angle of diffracction 30 degree
(b) the first man falls at angle of diffraction of 30 degrees. II question In a simple silt diffraction expriment first min for red light (660nm) conxides with first max of some other wavelength (lamda dash). Find the value of lamda dash.