Question

class10............​science​

Answer 1

$\huge\star{\green{\underline{\mathfrak{Answer :-}}}}$

The far point of a myopic eye is 80 cm.

The disease given here is :- Myopia.

Myopia or near sightedness is a eye disease in which we can see near objects but can not see far objects.

In this disease, the far point of an eye that is infinity comes to some point between the eye and infinity.

This can be due to :-

• Shortening of eye ball
• Increase in the focal length of the eye lens

To correct this disease we need concave lens.

The nature of such lens is that it diverges the light rays such that the eye lens converge them to meet the light rays on retina.

The power of the lens is :-$\tt\dfrac {1}{focal\:length\:in\:m}$

So, $\dfrac{1}{0.8}$ = -1.25 D

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