Question

A 2.0 m tall person is standing in front of a flat vertical mirror. What minimum height must the mirror have if the person is to see her entire body, from the top of her head to her feet?

Answer 1

Answer:

100cm

Explanation:

Since the eyes are 6 cm below the top of her head, the point of incidence of the ray must be

200cm-3cm=197cm

Since the eyes are 194 cm from her feet, the point of incidence of this ray must be

194cm/2=97cm

So the lower edge of the mirror must be 97 cm from the ground and the vertical dimension of the mirror must be 197 cm - 97 cm = 100 cm, which is half the height of the person.