A nearsighted man can clearly see object only upto a distance of 1 m and not beyond this. The power of the spectacles lens (in D) necessary for the remedy of this defect will be

Question

A nearsighted man can clearly see object only upto a distance of 1 m and not beyond this. The power of the spectacles lens (in D) necessary for the remedy of this defect will be (A) + 1 (B) -1 (C) +3 (D) none of these

Tardigrade Admin · Accepted Answer

For the remedy of nearsightedness spectracles with such a lens used which will brings object at

\infty

to his farthest distance of clear vision.

\frac{1}{v} - \frac{1}{u} = \frac{1}{f}

\frac{1}{- 1} - \frac{1}{\infty} = \frac{1}{f} = p

\Rightarrow p = - 1 D

Q. A nearsighted man can clearly see object only upto a distance of 1m and not beyond this. The power of the spectacles lens (in D) necessary for the remedy of this defect will be

+ 1

-1

+3

none of these

For the remedy of nearsightedness spectracles with such a lens used which will brings object at ∞ to his farthest distance of clear vision. v1​−u1​=f1​ −11​−∞1​=f1​=p ⇒p=−1D

Q. A nearsighted man can clearly see object only upto a distance of $1 m$ and not beyond this. The power of the spectacles lens (in D) necessary for the remedy of this defect will be

For the remedy of nearsightedness spectracles with such a lens used which will brings object at $\infty$ to his farthest distance of clear vision.

$\frac{1}{v} - \frac{1}{u} = \frac{1}{f}$
$\frac{1}{- 1} - \frac{1}{\infty} = \frac{1}{f} = p$
$\Rightarrow p = - 1 D$