Question

What are the lens formula, magnification, and power of the lens?

Answer 1

Spherical lens

The optical lenses have a spherical surface and a uniform radius of curvature across the whole lens is called the spherical lens. There are two types of spherical lens, such as:

1. Concave lens
2. Convex lens

Lens formula

$\frac{1}{\mathrm{v}}+\frac{1}{\mathrm{o}}=\frac{1}{\mathrm{f}}$

Here,

“$\mathrm{v}$” is the distance of the image formed from the optical center of the lens

“$\mathrm{o}$” is the distance of the object from the optical center of the lens.

“$\mathrm{f}$” is the focal length of the lens.

Magnification by lens formula

Magnification is characterized as the proportion of the height of the created picture to the elevation of the item. It is determined as the percentage of image distance to object distance in the terms of image and object distance.

$$\begin{gathered} \mathrm{m}=\frac{\mathrm{hv}}{\mathrm{ho}} \\ \mathrm{m}=\frac{\mathrm{h}}{\mathrm{o}} \end{gathered}$$

Here,

$\mathrm{m}$ is the magnification.

$\mathrm{hv}$ is the height of the image.

$\mathrm{ho}$ is the height of the object.

Power of lens

We define the power of the lens as the reciprocal of the focal length of the lens used.

$P=\frac{1}{F}$

1. SI unit of power is Dioptre ($\mathrm{D}$).
2. The power of the concave lens is negative.
3. The power of the convex lens can be positive.