The near point of a hyper metropic person is $50$ cm from the eye. What is the power of the lens required to enable the person to read clearly a book held at $25$ cm from the eye?

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Solution

For a hypermetropic eye $u = - 25 c m$ and $v = - 50 c m$

substituting in the lens formula we get focal length is $f = 50 c m$ $= 0.5 m$

From the formula,

$P = \frac{1}{f}$

$P = \frac{1}{0.52 D}$

so the power of the lens is $2$ dioptre and the nature of lens is a converging lens or a convex lens.

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The near point of a hyper metropic person is 50cm from the eye. What is the power of the lens required to enable the person to read clearly a book held at 25cm from the eye?

For a hypermetropic eye u=−25cm and v=−50cm substituting in the lens formula we get focal length is f=50cm =0.5m From the formula, P=1f P=10.52D so the power of the lens is 2 dioptre and the nature of lens is a converging lens or a convex lens.

The near point of a hyper metropic person is $50$ cm from the eye. What is the power of the lens required to enable the person to read clearly a book held at $25$ cm from the eye?