Question

Two thin lenses of power + 3.5 d and -2.5 d are placed in contact find the power and focal length of lens combination

Answer 1

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We know that:- Combination of power determined as the whole of power among focal length.


ACCORDING TO THE QUESTION

P=P1+P2

P=+3.5-2.5

P=1


Now...

FOCAL LENGTH

P=1/f

1=1/f

f=1/1

f=1m



Thanks!!!

Answer 2

Answer:

The answer to this question is 100cm.

See the attachment for the full answer.