Unit: waves
Year: 1989 Question#: 49
Question: When a ray of light strikes a mirror perpendicular to its surface, the angle of reflection is
(1 ) 0°
(2 ) 45°
(3 ) 60°
(4 ) 90°
What is this question really asking?
Explanation by: Allison B.
[ Return to question menu ]
Answer 1
0°
CORRECT
Since the ray strikes the mirror perpendicular to its surface, the angle of incidence is zero (from the normal). The law of reflection states that the angle of incidence equals the angle of reflection. So the angle or reflection would be 0°.
return to top
Answer 2
45°
INCORRECT
the law of reflection states that the angle of incidence (from the normal) equals the angle of reflection (from the normal). (see the picture) if the angle of reflection was 45 , the ray of light would have struck the mirror at an angle of 45°.
return to top Answer 3
60°
INCORRECT
the law of reflection states that the angle of incidence (from the normal) equals the angle of reflection (from the normal). (see the picture) if the angle of reflection was 60 , the ray of light would have struck the mirror at an angle of 60°.
return to top Answer 4
90°
INCORRECT
the law of reflection states that the angle of incidence (from the normal) equals the angle of reflection (from the normal). (see the picture) if the angle of reflection was 90 , the ray of light would have struck the mirror at an angle of 90°.
return to top What's this question really asking?
This question is asking if you understand the law of reflection and the word perpendicular.
return to top
