Question

A convex lens has focal length 2cm. Find the magnifying power, if image is formed at
i) infinity​

Answer 1

Answer:

The magnification power will be 13.5.

Explanation:

Given that,

Focal length f = 2.0 cm

Distance of image is formed by the  DDV that means,

Distance of image v = 25 cm

Using lens's formula of magnification power

Hence, The magnification power will be 13.5.

Hope this helps!! :3

Answer 2

Given:

Focal length, f = 2 cm

Image distance, v = ∞

To Find:

Magnification, m.

Solution:

By using lens formula,

$\frac{1}{f} = \frac{1}{v} - \frac{1}{u}$

$\frac{1}{2} = \frac{1}{ \infty } - \frac{1}{u}$

$\frac{1}{2} = 0 - \frac{1}{u}$

$\frac{1}{2} = \frac{ - 1}{u}$

u = -2 cm.

Magnifying power, m = v/u

m = ∞/-2

m = ∞

The magnifying power of the convex lens will be infinite when the image is formed at infinity.