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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

`-15 cm`

C

`+30 cm`

D

`-30 cm`

Text Solution

Verified by Experts

The correct Answer is:
D
Focal length of combination,
`(1)/(F)=(1)/(f_(1))+(1)/(f_(2))=(1)/(60)+(1)/((-20))rArr F=-30 cm`
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MHTCET PREVIOUS YEAR PAPERS AND PRACTICE PAPERS-RAY OPTICS-EXERCISE 1 (TOPICAL PROBLEMS)
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