A person's near point is `50 cm` and his far point `3m`. Power of the lenses he requires for
`(i)` reading and
`(ii)` for seeing distant stars are

Options

A. `-2D and 0.33D`
B. `2D and -0.33 D`
C. `-2D and 3D`
D. `2D and -3D`

Answer

B

Explanation

`(1)/(-3) -(1)/(oo) = (1)/(F)`
`rArr f=-3m`
`rArr P=(1)/(3)D= -0.33D`
For near point correction
`(1)/(-50cm)-(1)/(-25cm)=(1)/(f)`
`(1)/(50)=(1)/(f)`
`rArr f=50 cm = 0.5 m`
`rArr P=(1)/(0.5)=+2D`