A lens of 10.0-cm focal length is placed 29.0 cm to the right of the object and a mirror of focal length -20.0 cm is placed 49.0 cm to the right of the lens.Where is the image formed by the mirror?

Question

Quizplus · Accepted Answer

Using the lens formula, we can find the position of the object as:
1/f = 1/do - 1/di (where f is the focal length of the lens, do is the distance of the object from the lens, and di is the distance of the image from the lens)
1/10 = 1/29 - 1/di
di = 18.3 cm to the right of the lens

Now, using the mirror formula, we can find the position of the final image as:
1/f_mirror = 1/di - 1/do_mirror (where f_mirror is the focal length of the mirror, and do_mirror is the distance of the object from the mirror)
1/-20 = 1/18.3 - 1/do_mirror
do_mirror = -12.62 cm (the negative sign indicates that the object is behind the mirror)

Therefore, the final image is formed 12.62 cm to the right of the mirror. Answer choice D is the closest to this value.

A Lens of 10