JEE PHYSICS MCQ: RAY OPTICS

1 Medium

1 of 1

Application +4 | -1

A convex lens

A

of focal length

\mathrm{20}\,\,\mathrm{cm}

and a concave lens

B

of focal length

\mathrm{56}\,\,\mathrm{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 distances

d

in cm will be

View answer and explanation

Correct option: B

\mathrm{36}

Option B (36) is correct because the distance between the lenses must be equal to the difference of their focal lengths for the beam to remain parallel.

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