Karnataka Board PUCPUC Science 2nd PUC Class 12

A Nearsighted Person Cannot Clearly See Beyond 200 Cm. Find the Power of the Lens Needed to See Objects at Large Distances. - Physics

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Answer in Brief

A nearsighted person cannot clearly see beyond 200 cm. Find the power of the lens needed to see objects at large distances.

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Solution

For a near-sighted person, u = ∞.
Now, we have:

v = – 200 cm = – 2 m
The lens formula is given by

`1/v -1/u =1/f`

On putting the respective values, we get:

`1/f = 1/((-2)) -1/∞ =-1/2`

∴ The power of the lens = `1/f`= -0.5 D

Concept: Lenses
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Chapter 19: Optical Instruments - Exercise [Page 432]

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HC Verma Class 11, Class 12 Concepts of Physics Vol. 1
Chapter 19 Optical Instruments
Exercise | Q 16 | Page 432

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