The far point of a myopic person is `150 cm` in front of the eye. Calculate the focal length and power of a lens required to enable him to see distant objects clearly.

Answer

`-1.5 m, -0.67 D`

Explanation

Here, `v = x = -150 cm, u = oo, f = ?`
from `(1)/(f)=(1)/(v)-(1)/(u)=(1)/(-150)-(1)/(oo)`
`f = -150 cm = -1.5 m`
`P = (1)/(f) = (1)/(-1.5) = -0.67 D`.