Question

define the first and second principal focus of both concave and convex lens​

Answer 1

Explanation:

Explanation:(Second principal focus and second focal length :

Explanation:(Second principal focus and second focal length :It is a fixed point on the principal axis such that the light rays incident parallel to the principal axis, after refraction through the lens, either converge to this point (in convex lens) or appear to diverge from this point (in concave lens).

Answer 2

Answer:

(B) Second principal focus and second focal length :

It is a fixed point on the principal axis such that the light rays incident parallel to the principal axis, after refraction through the lens, either converge to this point (in convex lens) or appear to diverge from this point (in concave lens).