(i) At what distance should the lens be held from the card sheet in order to view the squares distinctly with the maximum possible magnifying power ?
(ii) What is the magnification in this case ?
(iii) Is the magnification equal to magnifying power in this case ? Explain.

Explanation

(i) Here, `v = -25 cm, f = 10 cm, u = ?`
As `(1)/(v)-(1)/(u)=(1)/(f) :. (1)/(u)=(1)/(v)-(1)/(f)=(1)/(-25)-(1)/(10)=(-2 - 5)/(50)`
`u = (-50)/(7) = -7.14 cm`
(ii) Magnification, `m = (v)/(|u|) = (25)/(7.14) = 3.5`
(iii) Magnifying power `=(d)/(u)=(25)/(7.14) = 3.5`
Yes, the magnification and magnifying power in this case are equal, because image is formed at the least distance of distinct vision.