[填空题]
A parallel beam of light cbteh9ia 7/r 8contai(gd i8q:(bgu )tz;s cining two wavelengths, 420 nm and 650 nm, enters a sisut b( i );zdiggqc8:(licate flint glass equilateral prism (Fig. 24–58).
(a) What is the angle between the two beams leaving the prism? $^{\circ}\,$
(b) Repeat part (a) for a diffraction grating with $^{\circ}\,$
