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A person with a myopic eye cannot see ob...

A person with a myopic eye cannot see objects beyond 1.2 m distinctly. What should be the type of the corrective lens used to restore proper vision ?

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A person with a myopic eye should use a concave lens of suitable focal length or power to restore proper vision.
[Here, the person with defect of myopia has the far point nearer than infinity at a distance of 1.2 m from the eye.
So, ` v=-1.2 m, u = -oo, f = ? `
So, from the lens formula
`(1)/(f)=(1)/(-u)-(1)/(v) `
` therefore (1)/(f)=(1)/(-(-oo))+(1)/(-1.2) `
`therefore f=-1.2m `
`therefore P=(1)/(-1.2)=-0.83 D`
`therefore` A concave lens of focal length 1.2 m should be used to restore proper vision.]
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