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In figure, an air lens of radius of curv...

In figure, an air lens of radius of curvature of each surface equal to `10 cm` is cut into a cylinder of glass of refractive index `1.5.` The focal length and the nature of lens are

A

15cm,concave

B

15 cm,convex

C

`oo`,neither concave nor convex

D

0,concave

Text Solution

Verified by Experts

The correct Answer is:
A
(a) For air lens in glass, focal length of air lens,
`1/f=(""_(g)µ_(a)-1)(1/R_(1)-1/R_(2))`
`=(2/3-1)[1/10-(-1/10)]`
`rArr`f=-15 cm
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DC PANDEY ENGLISH-RAY OPTICS-Checkpoint 9.4
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  4. A plano convex lens is made of glass of refractive index 1.5. The radi...

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  5. At what distance from a convex lens of focal length 30cm an object sh...

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  6. A plano-convex lens is made of flint glass, its focal length is

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  7. Distance of an object from a concave lens of focal length 20 cm is 40 ...

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  8. Where should an object be placed from a converging lens of focal lengt...

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  9. An object is placed at 10 cm from a lens and real image is formed with...

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  10. The real image which is exactly equal to the size of an object is to b...

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  11. A plano-convex lens of curvature of 30 cm and refractive index 1.5 pro...

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  15. Two thin lenses, one of focal length + 60 cm and the other of focal le...

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  16. A convex lens of focal length 40 cm is in contact with a concave lens ...

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  17. Two similar planoconvex lenses are combined together in three differen...

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  18. A convex lens of focal length f cut into parts first horizontally and ...

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