Question

A 5.0-cm-high object is situated 17.0 cm in front of a concave mirror that has a radius of curvature of 10.0 cm. Use a ray diagram drawn to scale, measure the following. The mirror must be drawn to scale.

(a) the image distance (include the sign)

(b) the height of the image

Answer 1

The focal distance is ½ * radius of curvature
f = 5 cm
do = 17.0 cm

1/f = 1/do + 1/di
1/5 = 1/17 + 1/di
Multiply both sides by (5 * 17 * di)

17 * di = 5 * di + 5 * 17
Subtract 5 * di from both sides

12 di = 85

di = 85/12 = 7.08

The height ratio = the distance ratio
ho/hi = do/di

5.0/ hi =17/7.08
hi = 2.08