Question

The far point of a near-sighted person is 6.0 m from her eyes, and she wears contacts that
enable her to see distant objects clearly. A tree is 18.0 m away and 2.0 m high. (a) When she
looks through the contacts at the tree, what is its image distance? (b) How high is the image
formed by the contacts?

Answer 1

The far point of a near-sighted person is 6.0 m from her eyes, and she wears contacts that

enable her to see distant objects clearly. A tree is 18.0 m away and 2.0 m high. (a) When she

looks through the contacts at the tree, what is its image distance? (b) How high is the image

formed by the contacts?

Explanation:

The far point of 6.0 cm illustrates that the focal length of the lens is f = –6.0m, u = – 18 m and h = 2m.

1/f =  1/v  - 1/u

1/v = 1/f+ 1/u

= 1/-6.0  - 1/18.0

v= -4.5

To find the image size:

h' = h(v/u)

=2* {-4.5/-18.0}

=0.50meters