Question

A simple microscope is rated 5X for a normal relaxed eye. What will be its magnifying power for a farsighted man whose near point is 40cm ?

• A. 5 X
• B. 3 X
• C. 8 X
• D. 13 X

Answer 1

The correct option is C 8 X

For the relaxed eye of a normal man, the near point is 25 cm
Now,
the magnification produced is directly proportional to the near point of the eye.

$\frac{m_2}{m_1}=\frac{D_2}{D_1}$

Putting $D_2=40$ and $D_1=25$

We get the new magnification as $8X$