申論題

15. The figure shows three situations in which a white light ray (W) undergoes dispersion at an interface (only the blue and red components are drawn). The dashed line shows the straight-through (no deflection) direction. In which are the refracted rays physically possible?

(A) 1 and 2 (B) 1 and 3 (C) 2 and 3 (D) 2 only (E) all three