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Two thin lenses, one of focal length + 6...

Two thin lenses, one of focal length + 60 cm and the other of focal length – 20 cm are put in contact. The combined focal length is

A

`=15 cm`

B

`-15cm`

C

`=30 cm`

D

`-30 cm`

Text Solution

Verified by Experts

The correct Answer is:
D
(d) Focal length of combination,
`1/F==1/(f_(1))+1/(f_(2))=1/60+1/((-20))rArrF=-30cm`
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DC PANDEY-RAY OPTICS-Checkpoint 9.4
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