Question

A person wears eyeglass of focal length -70 cm what is the far point of the person?

Answer 1

Using lens formula,

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

f = -70cm

u = -$\infty$

$\frac{1}{-70}$ - $\frac{1}{v}$ = $\frac{1}{-\infty }$

$\frac{1}{v}$ = $\frac{1}{-70}$

v = -70cm