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A nearsighted man can clearly see object...

A nearsighted man can clearly see objects up to a distance of 1.5m. Calculate the power of the lens of the spectacles necessary for the remedy of this defect.

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The lens should form a virtul image of a distance object at 1.5 m form the lens. Thus, it should be a divergent lens andits focal length should be -1.5 m. Hence
f-1.5 m
`or P=1/f=-11.5m^-1=0.67D.`
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HC VERMA-OPTICAL INSTRUMENTS-Exercises
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  6. Find the maximum magnifying power of a compound microscope having a 25...

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  8. An eye can distinguish between two points of an object if they are sep...

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  13. The eyepiece of an astronomical telescope has a focal length of 10 cm....

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  14. A Galilean telescope is 27 cm long when focussed to form an image at i...

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  15. A farsighted person cannot see objects placed closer to 50 cm. Find th...

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  16. A nearsighted person cannot clearly see beyond 200 cm. Find the power ...

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  17. A person wears glasses of power - 2.5 D. Is the person short sighted o...

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  19. A normal eye has retina 2 cm behind the eye-lens. What is the power of...

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  20. The near point and the far point of a child are at 10 cm and 100 cm. I...

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