A convex lens A of focal length `20 cm` and a concave lens B of focal length `5 cm` are kept along the same axis with a distance d between them. If a parallel beam of light falling on A and B as a parallel beam, then d is equal to ……cm

A convex lens A of focal length 20cm and a concave lens B of focal length 5cm are kept along the same axis with a distance d between them. I a parallel lbeam of leight falling on A leaved B as a parallel beam, then d is equal to "____________" cm.

A convex lens A of focal length 20cm and a concave lens B of focal length 5cm are kept along the same axis with a distance d between them. I a parallel lbeam of leight falling on A leaved B as a parallel beam, then d is equal to "____________" cm.

A convex lens A of focal length 20cm and a concave lens B of focal length 10 cm are kept along the same axis with a distance d between them. If a parallel beam, then d is

A convex lens A of focal length 20cm and a concave lens B of focal length 10 cm are kept along the same axis with a distance d between them. If a parallel beam, then d is

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

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

A convex lens A of focal length 20 cm and a concave lens B of focal length 5 cm are kept along the same axis with a distance d between them. What is the value of d if a parallel beam of light incident on A leaves B as a parallel beam ?

A convex lens of focal length 10cm and concave lens of focal length 20 cm are kept 5 cm apart. The focal length of the equivalent lens is