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A point source of light is placed 4m bel...

A point source of light is placed `4m` below the surface of a liquid of refractive index `5//3`. The minimum diameter of a disc, which should be placed over the source, on the surface of the liquid to cut off all light out of water, is

A

`oo`

B

`6m`

C

`4m`

D

`3m`

Text Solution

Verified by Experts

The correct Answer is:
B
`R=(h)/(sqrt(mu^2-1))=(4)/(sqrt((5/3)^2-1))=(4xx3)/(4)=3m`
Diameter `d=2R=6m`
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CP SINGH-REFRACTION OF LIGHT BY PLANE SURFACES-Exercises
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  2. A fish looking up through the water sees the outside world contained i...

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  3. A point source of light is placed 4m below the surface of a liquid of ...

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  5. A light beam is travelling from Region I to IV (figure). The refractiv...

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  6. A transparent solid cylindrical rod has a refractive index of (2)/(sqr...

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  7. Light enters at an angle of incidence in a transparent rod of refracti...

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  8. When light is incident on a medium at angle i and refracted into a sec...

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  9. A rectangular slab ABCD, of refractive index n1 , is immersed in water...

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  10. A ray of light travels from an optically denser to rarer medium. The c...

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  11. A ray of light travels from a medium of refractive index mu to air. It...

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  12. The reason for shining of air bubble in water is

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  13. Which of the following is not due to total internal reflection ?

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  14. Consider telecommunication through optical fibres. Which of the follow...

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  15. Pick out the correct staments about optical fibres from the following:...

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  16. Which of the following options are correct regarding prism?

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  17. When a ray of light is refracted by a prism such that the angle of dev...

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  18. Deviation delta produced by a prism of angle A, which is assumed to be...

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  19. The refracting angle of a prism is A and refractive index of the mater...

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  20. If the refracting angle of a prism is 60^@ and the minimum deviation i...

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