Question

An object 1.30 cm1.30 cm high is held 3.00 cm3.00 cm from a person's cornea, and its reflected image is measured to be 0.167 cm0.167 cm high. What is the magnification?

magnification:_____

Where is the image?

image distance: ______cm

Find the magnitude of the radius of curvature of the convex mirror formed by the cornea.

the magnitude of the radius of curvature:______cm

Note: This technique is used by optometrists to measure the curvature of the cornea for contact lens fitting. The instrument used is called a keratometer, or curve measurer.

Answer 1

Given,

height of the object

height of the image

object distance

(a) The magnification is given by,

Magnification is 0.13.

(b) Let the image distance be .

We have,

Image distance is 0.39cm.

(c) Let the focal length of the mirror be .

By mirror formula,

Therefore, the Radius of curvature is given by,

Radius of curvature is 0.90cm.