Physics, asked by tekumatlanarsimha, 1 month ago

a concave lens and concave lens of focal length +20cm and -30cm respectively then find the power of each lens find the focal length of combined lens and find the combined power of the lenses​

Answers

Answered by TalkToLeg
0

Answer:

Correct option is

C

+5D

Given: Two lens of focal length, f

1

=−20cm and f

2

=+10cm are put in combination

To find the power of the combination.

Solution:

If focal length of the combined lens is F

Use the formula,

F

1

=

f

1

1

+

f

2

1

F

1

=

(−20)

1

+

10

1

F

1

=

20

−1+2

⟹F=20cm=0.2m

So the power of the combination is,

P=

0.2

1

=+5D

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