i) Find the angular separation between the red hydrogen-αspectral line at 656 nm and the yellow sodium line at 589 nm if thetwo lines are observed in third order with a diffraction gratinghaving 3 500 slits per cm. (Give the answer in degrees, correct tothree significant figures.) [6]
           (ii) Using the same diffraction grating as in (i) , what is thehighest order that could possibly be observed using violet light ofwavelength 420 nm?
