Question

Give definition of first and second focus of lens.
Draw a ray-diagram showing the image formation
an object placed at 2F of a convex lens.​

Answer 1

Answer:

hope this helps...

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).

and for the ray  diagram check the attachment.