Question

the near point of a short sighteded person is 10 cm and he desires to read a book 30cm away from him. the power of lens to be used him​

Answer 1

The near point of a short sighted person is 10 cm and he desires to read a book 30 cm away from him.

To find : The power of lens to be used by him.

solution : object distance, u = near point of short sighted person = -10 cm

image distance, v = -30cm

using formula,

1/v - 1/u = 1/f

⇒1/-30 - 1/-10 = 1/f

⇒-1/30 + 1/10 = 1/f

⇒-1/30 + 3/30 = 1/f

⇒1/15 = 1/f

⇒f = 15 cm

now power of lens = 100/f (in cm) = 100/15 = 6.67D

Therefore the power of lens to be used by him is +6.67D

Answer 2

Answer:

+6.67 d

Explanation:

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