Question

Which of the following is NOT true for a spherical concave mirror? a. it cannot produce virtual images
b. its focal length is half its radius
c. its focal length is positive
d. it can produce upright images

Answer 1

Answer:

Its focal length is positive

Explanation:

A concave mirror is shown in attached figure. The distance from the pole to the focus of the mirror is called its focal length. Spherical mirrors are a part of a sphere.

As per conventions, we know that the axis opposite to x axis is taken as negative.

So, it is clear that the focal length of spherical concave mirror is negative.

Hence, the incorrect option is (c) " its focal length is positive".