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What focal length should the reading spe...

What focal length should the reading spectacles have for a person whose near point is `50cm` ? (NCERT Solved Example)

A

`25 cm`

B

`50 cm`

C

`- 50 cm`

D

`25 cm`

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Verified by Experts

The correct Answer is:
B
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PRADEEP-OPTICS-Exercise
  1. The final image in a astronomical telescope (w.r.t. object) is.

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  2. A telescope uses an objective lens of focal length f0 and an eye lens ...

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  3. What focal length should the reading spectacles have for a person whos...

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  4. An astronomical telescope has a magnifying power of 10. In normal adju...

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  5. A myopia eye can see clearly………but the………cannot be seen distinctly.

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  6. A myopia eye can see clearly………but the………cannot be seen distinctly.

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  7. Presbyopia is also called………. .

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  8. For a normal eye, the least distance of distinct vision is……..and far ...

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  9. Magnifying power of a simple microscope is defined as the………of angles…...

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  10. In a compound microscope, the objective lens and……..are………. .

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  11. Focussing in a compound microscope is carried out by changing the……..f...

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  12. In an astronomical telescope, the distance between……….and…….can be var...

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  13. In normal adjusment of telescope, final image is……. . And distance bet...

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  14. In Cassegrainian telescope, objective lens is………by………… .

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  15. The far point of a myopic person is 150 cm in front of the eye. Calcul...

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  16. A short sighted person is wearing specs of power -3.5 D. His doctor pr...

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  17. A short sighted person cannot see clearly beyond 2 m. Calculate power ...

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  18. A myopic person can see things clearly only when they lie between 10 c...

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  19. A person cannot see the objects distinctly, when placed at a distance ...

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  20. The distance of distinct vision of a person is 50 cm. He wants to read...

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