A convex lens of focal length 0.25 m

An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal length of the lens upto two places of decimal.

The image formed by a convex lens when the distance of the object from the lens is large is

A plano-convex lens has a focal length f= 0.19 m. The radius of curvature of the convex side of the lens has been determined to be 0.08 m and the radius of curvature of the flat side is assumed to be infinite.Calculate the refractive index of the lens. Express answer to two decimal places.

An object is placed at a distance of 20 cm from a convex lens of focal length 10 cm. The image is formed on the other side of the lens at a distance20 cm10 cm40 cm30 cm

A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept alongthe same axis with a distance d between them. If a parallel beam of light falling on A leaves B asa parallel beam, then the distance d in cm will be