A convex lens A of focal length 20 cm and a concave lens G of focal length 5 cm 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

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Solution

The correct option is B 15
distance between is $20 - 5 = 15$
as image formed by lens must be at the focus of the second lens to get final image at infinity
option $B$ is correct

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Similar questions

Q. 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 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 with a focal length of 20 cm and a concave lens B with a focal length of 5 cm is 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

Q. A convex lens

A

of focal length

20 c m

and a concave lens

B

of focal length

5 c m

are kept along the same axis with a distance

^{'} d^{'}

between them as shown in a figure. If a parallel beam falling on

A

emerges parallel from

B

, then

^{'} d^{'}

is equal to

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 distace d between them. If a parallel beam of light falling on A leaves B as a parallel beam, then d is equal to
(IIT-JEE 1985)

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A convex lens A of focal length 20 cm and a concave lens G of focal length 5 cm 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

The correct option is B 15distance between is 20−5=15 as image formed by lens must be at the focus of the second lens to get final image at infinityoption B is correct

The correct option is B 15
distance between is $20 - 5 = 15$
as image formed by lens must be at the focus of the second lens to get final image at infinity
option $B$ is correct