Question Detail

PHY 104 Reflection and Refraction of Light Objective Question
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Question

For a person 1.60 m tall with eyes 10 cm below the top of her head, what is the minimum height a vertical plane mirror must be for her to see her whole body, and how far must its lower edge be from the floor?
Options
A 80 cm high, 75 cm off the floor
Correct Answer
B 160 cm high, 0 cm off the floor
C 75 cm high, 80 cm off the floor
D Half her height, with the lower edge halfway between her feet and eyes.
Correct Answer

Option A is the correct answer.

Detailed Explanation

According to the solution provided on page 16 for Example 32-2, 'Geometry then shows that the mirror must be 80 cm high, with its bottom 75 cm off the floor.'

Hint

Consider the geometry of reflection: to see your feet, the mirror's bottom edge must be halfway between your feet and eyes. To see your head, the mirror's top edge must be halfway between your eyes and the top of your head.

Question Info

Course: PHY 104
Topic: Reflection and Refraction of Light
Type: Objective
Difficulty: Not specified
Question 17 of 947
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