Light Waves
3 marks · EasyA ray of light strikes a flat mirror as shown in the diagram below.
On the diagram, draw the normal at the point B where the ray meets the mirror.
Label the angle of incidence on your diagram.
Sketch the reflected ray and label it.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
(a) A straight line perpendicular to the mirror at point B. · must show normal drawn at B, 90° to mirror
(b) The angle between the incident ray and normal labelled as angle of incidence. · must show angle of incidence labelled correctly
(c) Ray drawn leaving B making equal angle to normal as incident ray, labelled as reflected ray. · must show reflected ray leaving at correct angle, labelled
Common mistakes: normal not at right angles; angle marked on wrong side; reflected ray at incorrect angle
Show mark scheme and worked solution
Marking points
B1 (a) · 1 mark · Draws the normal at right angles (90°) to the mirror at B.
B1 (b) · 1 mark · Correctly labels the angle of incidence between normal and incident ray.
B1 (c) · 1 mark · Draws reflected ray at equal angle to the normal and labels as 'reflected ray'.
Worked solution
a) The normal is a line perpendicular to the mirror at point B. b) Label the angle between the incident ray and the normal as 'angle of incidence'. c) Draw the reflected ray leaving B so that the angle to the normal equals the angle of incidence. Label this ray as 'reflected ray'.