Question

A plane mirror and a concave mirror (f = 8 cm) are facing each other and are separated by a distance of 20 cm. An
object is placed 10 cm in front of the plane mirror. Assume that the light from the object first falls on the plane
mirror and after reflection from the plane mirror falls on the concave mirror. Locate the final image and the
nature of image. Also draw a-rough ray diagram.​

Answer 1

Answer:

The parallel rays incident on the convex lens converge at the focus,F of the lens. At the mirror, after reflection forms an image at the optical centre of the lens, C.

Thus, the image of the virtual point object Fis formed at C.

f = CF

=CM + MF

= 10 + 10

= 20 cm

Thus, the focal length of the lens is 20 cm.