Question

Find focal length of concave lens using convex lens

Answer 1

Answer:

To determine focal length of a convex lens

Place the holder with the screen on the bench. The position of the screen should be such that the sharp image of the distant object is obtained on it. The difference between the position of the lens and the screen is equal to the focal length of the given convex lens.

Answer 2

$\sf\pink{Answer\:-}$

To determine rough focal length of convex lens :

• Clamp the holder with lens in a fixed upright and keep the upright at 50 cm mark.
• Adjust the lens such that its surface is vertical and perpendicular to the length of the optical bench.
• Keep the upright fixed in this position throughout.