Question

The projection lens in a certain projector is a single thin lens. An object 23.7 mm high is to be projected so that its image fills a screen 1.71 m high. The lens-to-screen distance is 3.04 m. Determine the focal length of the lens.

Answer 1

Answer:

-0.0426 m

Explanation:

-i / o = h' / h

-1.71 / 0.0237 = 3.04 /o

o = -0.042

1/o + 1/i = 1/f

1/(-0.042) + 1/(3.04) = 1/f

-23.81 +0.329 = 1/f

-23.481 = 1/f

f = -0.0426 m