Two converging lenses,the first with focal length 10.0 cm and the second with focal length 20.0 cm,are separated by 40.0 cm.An object,3.00 cm in height,is placed 30.0 cm in front of the first lens.Where is the image caused by the first lens?
A) 7.50 cm after the first lens
B) 7.50 cm after the second lens
C) 15.0 cm after the first lens
D) 15.0 cm after the second lens
E) 55.0 cm after the second lens

Question

Quizplus · Accepted Answer

Using the thin lens equation, we can find the image distance formed by the first lens:

1/f = 1/do + 1/di

where f is the focal length, do is the object distance, and di is the image distance.

Substituting the given values:

1/10 = 1/30 + 1/di

Solving for di, we get:

di = 15.0 cm

Therefore, the image formed by the first lens is 15.0 cm after the first lens.

Two Converging Lenses,the First with Focal Length 10