Question

A spherical mirror and a thin spherical lens have each a focal length of −15 cm. The mirror and the lens are likely to be

• A. both concave
• B. both convex
• C. the mirror is concave and the lens is convex
• D. the mirror is convex, but the lens is concave.

Answer 1

The Correct Option is A

Concave mirrors and concave lenses are conventionally assigned negative focal lengths, indicating their concave nature. Therefore, both the spherical mirror and the thin spherical lens are concave.

The correct choice is (A), signifying both are concave.