Light Waves
3 marks · NormalA ray of light strikes a plane mirror at an angle of 36° to the normal.
State the law of reflection.
Calculate the angle of reflection.
If the angle of incidence is increased to 48°, what will the new angle of reflection be?
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Show answer
(a) The angle of incidence equals the angle of reflection.
(b) 36° deg
(c) 48° deg
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Correct law stated: angle of incidence = angle of reflection.
A1 (b) · 1 mark · Correct angle of reflection calculated as 36°.
A1 (c) · 1 mark · Correct value for new angle of reflection: 48°. Allow follow-through on candidate's answer if (a) misunderstood law in (b). (follow-through)
Worked solution
a) The law of reflection states that the angle of incidence is equal to the angle of reflection. b) Angle of reflection = angle of incidence = 36°. c) If the angle of incidence is increased to 48°, the angle of reflection is also 48°.