A person wears glasses of power `-2.5D`. The defect of the eye and the far point of the person without the glasses are, respectively

Options

A. farsightedness,`40cm`
B. nearsightedness, `40 cm`
C. astigmatism, `40 cm`
D. nearsightedness, `250 cm`

Answer

B

Explanation

`f = (100)/(P)cm = (100)/(-2.5)=- 40cm`
`(1)/(-(F.P.)) - (1)/(-("distance of object")) = (1)/(f)`
`(1)/(-(F.P.)) - (1)/(oo)=(1)/(-40) rArr F.P. = 40cm`
`F.P. = 40 cm`, nersightedness