A person with a myopic eye cannot see objects beyond 2m distinctly. If he wants to see an object at 50m then power of his required lens

The person has a near point at 2m instead of the normal 25cm (0.25m). The power of the lens needed to correct this myopia can be calculated using the lens formula:

1/f = 1/v - 1/u

Where: f is the focal length of the lens, v is the image distance (which is at the near point, -0.25m), u is the object distance (which is -2m for the person).

Substituting the values into the formula, we get:

1/f = 1/-0.25 - 1/-2

Solving this equation gives us f = -0.333m.

The power P of a lens is the reciprocal of its focal length in meters. Therefore, the power of the lens needed is:

P = 1/f = -3D (diopters)

However, this lens will only correct the person's vision for viewing objects at 2m. If the person wants to see objects clearly at 50m, we need to use the same formula but with u = -50m:

1/f = 1/-0.25 - 1/-50

Solving this equation gives us f = -0.265m, and therefore the power of the lens needed is:

P = 1/f = -3.77D (diopters)

So, the person would need a lens with a power of -3.77D to see objects clearly at 50m.