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The dispersive powers of the materials o...

The dispersive powers of the materials of the two lenses are in the ratio `4:3`.If the combination of these two lenses is of focal length 60 cm,then the focal lengths of the component lenses are:

A

`+15 cm and -20 cm`

B

`-15 cm and -20 cm`

C

`+20 cm and -25 cm`

D

`-20 cmand +25 cm`.

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MODERN PUBLICATION-UNIT TEST -06-EXERCISE
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  4. Retina of eye corresponds to which part of camera?

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  5. The ability of eye-lens to adjust its focal length is called……. .

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  6. An astronomical telescope of ten fold angular magnification has a leng...

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  8. To increse magnifying power of telescope,we sould increase:

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  9. A telescope has focal elngth of objective and eyepiece as 200 cm and 5...

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  10. If size of aperture is decreased,

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  11. The objective with large aperture are used in telescope for

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  14. Which of the following does not support the wave nature of light?

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