Question

If the person can't accommodate and the glasses is + 2.50d, at which distance will the person see clearly

Answer 1

Power of the glasses required is given as +2.5 D

this shows that person is having Farsightedness in which he can objects placed far clearly but he is not able to see clearly to the near objects

For normal vision near point of eye is 25 cm

Let say person can see the objects clearly at distance "d" from the eye

now from the formula

$\frac{1}{d_i} + \frac{1}{d_o} = \frac{1}{f}$

here given that

$\frac{1}{f} = 2.5$

$f = 40 cm$

also we know that

$d_o = 25 cm$

from above equation now

$\frac{1}{d} + \frac{1}{25} = \frac{1}{40}$

$d = 66.6 cm$

So the distance of object must be 66.6 cm

Answer 2

The answer would be 40 centimeters