How to know that the given focal length/dictance is positive or negative

Asked by  | 24th Feb, 2008, 11:30: AM

Expert Answer:

How to know that the given focal length/dictance is positive or negative.

It will give in the question that the mirror is concave/convex or lens is convex/concave.

The focal length of Concave mirror/Concave lens is negative while the focal length of convex mirror/convex lens is positive as per the New Sign Cartesian convention.

Rgds

Physics Expert

Answered by  | 7th Dec, 2017, 03:48: PM