Question

2.
A convex lens forms a real and inverted image of a needle at a distance
of 50 cm from it. Where is the needle placed in front of the convex lens
if the image is equal to the size of the object? Also, find the power of the
lens.​

Answer 1

Answer:

$+ 4d$

is the answer.

Answer 2

The position of the image should be at 2F since the image is the real and same size.

It is given that the image of the needle is formed at a distance of 50 cm from the convex lens. Therefore, the needle is placed in front of the lens at a distance of 50 cm.