Optics Problems - Numerical 05

05.

An object of size 3.0 cm is placed 14 cm in front of a concave lens of focal length 21 cm. Describe the image produced by the lens. What happens if the object is moved farther from the lens?

Suggested solution:

O = 3.0 cm, u = -14, f = -21 cm

On simplification, v = -8.4 cm

The image is erect, virtual and located 8.4 cm from the lens on the same side as the object.

As the object is moved away from the lens, the virtual image moves towards the focus of the lens but never beyond. The image progressively diminishes in size.