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Question
Choose the correct alternative and rewrite the following sentence.
A ray of light strikes the glass slab at an angle of 50°. What is the angle of incidence?
Options
50°
90°
60°
40°
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Solution
40°
The ray of light strikes at an angle of 50 with the horizontal. The angle of incidence is with respect to the normal, so the angle of incidence is 90° − 50° = 40°.
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