Question

to find the focal length of a concave lens using a convex lens (source of error) needed urgently minimum 3 pls fast​

Answer 1

Explanation:

Note the position of the index mark at the base of the image needle upright. Record the position of the index marks. Now place the concave lens holder on the I side of the convex lens. The upright and convex lens should be placed at a distance from each other.