A convex lens A of focal length 20 cm 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 of light falling on A leaves B as 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 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 of focal length 25 cm and a concave lens of focal length 10 cm are joined together. The power of the combination will be

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

A thin convex lens of focal length 10 cm and a thin concave lens of focal length 26.2 cm are in contact. The combination acts as

If a convex lens of focal length 20 cm and a concave lens of focal length 30 cm are kept in contract with each other. What will the power of the combination ?

A convex lens of focal length 40 cm is in contact with a concave lens of focal length 25 cm. The power of the combination is