都都都都係一條物理

(a) Use Snell's law, sin(60)/sin(w) = 1.5
hence, w = arc-sin[sin(60)/1.5] = 35.26 degrees

angle X = (90 - 35.26) degrees = 54.74 degrees
By Law of reflection, angle Y = angle X = 54.74 degrees

Let the angle of incident at surface CD be i,
then angle i = (90- 54.74) degrees = 35.26 degrees

Applying Snell's Law at the surface CD,
sin(35.26)/sin(z) = 1/1.5
i.e. sin(z) = (1.5)sin(35.26)
z = arc-sin[(1.5)sin(35.26)] = 60 degrees

(b) The two angles are equal.

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