A convex lens of focal length 10 cm and image formed by it, is at least distance of distinct vision then the magnifying power is

Question

A convex lens of focal length 10 cm and image formed by it, is at least distance of distinct vision then the magnifying power is (A) 3.5 (B) 2.5 (C) 1.5 (D) 1.4

Tardigrade Admin · Accepted Answer

The coverging lens used for magnification is called simple microscope or a magnifier.
When image is formed at

D

, the least distance of distinct vision, then magnifying power

M = 1 + \frac{D}{f}

Given,

D

= 25 cm,

f

= 10 cm

∴ M = 1 + \frac{25}{10} = 1 + 2.5 = 3.5

Q. A convex lens of focal length $10 c m$ and image formed by it, is at least distance of distinct vision then the magnifying power is

$3.5$

$2.5$

$1.5$

$1.4$

The coverging lens used for magnification is called simple microscope or a magnifier.
When image is formed at $D$ , the least distance of distinct vision, then magnifying power
$M = 1 + \frac{D}{f}$
Given, $D$ = 25 cm, $f$ = 10 cm
$∴ M = 1 + \frac{25}{10} = 1 + 2.5 = 3.5$

Q. A convex lens of focal length 10cm and image formed by it, is at least distance of distinct vision then the magnifying power is

3.5

2.5

1.5

1.4