Question

the focal length of a concave mirror and convex lens is positive or negative

Answer 1

Now the convex lens converges theincident rays. Hence the rays converge to a single point infront of the lens. Sothe image distance is positive here. you can easily verify that the focal length is in the positive x direction for a convex lens while it is along the negative x direction for a concave lens.

Answer 2

❤❤HERE IS YOUR ANSWER ❤❤

Focal length of CONCAVE MIRROR:-

-ve

Focal length of CONVEX MIRROR:-

+ve

❤❤div❤❤