Question

Use the mirror equation to deduce that an object placed between f and 2f of a concave mirror produces a real image beyond 2f.

Answer 1

For a concave mirror, the focal length (f) is negative.

∴f < 0

When the object is placed on the left side of the mirror, the object distance (u) is negative.

∴u < 0

For image distance v, we can write the lens formula as:

The object lies between f and 2f.

Using equation (1), we get:

∴is negative, i.e., v is negative.

Therefore, the image lies beyond 2f.