biconvex lens - Overview, Structure, Properties & Uses

Biconvex Lens - Properties, Formula, Uses, FAQs

Edited By Team Careers360 | Updated on May 24, 2022 09:12 AM IST

The biconvex lens is one of the lenses which is made up of two different convex surfaces that form a spherical shape. This lens has some radius of curvature. The other term that represents the biconvex lens is the convex-convex lens. In this article, let us see about the biconvex lens, biconvex mirrors, double convex lens, the difference between the biconcave lens and a biconvex lens. This kind of biconvex lens is very simple but is used in various fields and contains a lot of applications. For example, the biconvex lens has more applications in the field of laser beams, optical instruments, quality imaging and so on.

JEE Main 2025: Physics Formula | Study Materials | High Scoring Topics | Preparation Guide

JEE Main 2025: Syllabus | Sample Papers | Mock Tests | PYQs | Study Plan 100 Days

NEET 2025: Syllabus | High Scoring Topics | PYQs

What are the terms used in the Biconvex lens?

Focus:

In the biconvex lens, a collimated light beam or the light beam which is accurately parallel to each other is allowed to pass through the biconvex lens and the light beams converge at a particular spot. This spot can be defined as the focus.

Optical Centre:

The centre of the lens is known as the optical centre.

Also read -

Focal length:

The length or distance between the centre of the lens and the focus can be called the focal length.

Principal axis:

The axis or the line that cuts the convex lens horizontally and passes through the optical center of the lens, is called the principal axis.

The usage of biconvex lens in the human eye:

The best example of the biconvex lens is the eyes lens used for the rectification of human eye defects. In the working mechanism of the human eye, when the light rays which come from the object or target enter into the eye, bend sharp and fall on the focus of the retina. The light beam which is coming from a large distance needs only less refraction. For the higher convex lens, the refraction is greater.

NCERT Physics Notes :

JEE Main Highest Scoring Chapters & Topics

Just Study 40% Syllabus and Score upto 100%

Download E-book

Properties of biconvex lens:

Some basic properties of the biconvex lens are listed below:

The focal length of the biconvex lens is found to be in the positive axis
The focal length of the biconvex lens is found to be very shorter than the concave lens
The incident light converges in the biconvex lens.
The output images are found to be both real and virtual images, it depends on the length of the object from lens.
To minimize the spherical aberration, coma and distortion, the biconvex lens is used in practice.
The biconvex lens is symmetrical as it is made up of two exact convex lenses with the same radii of curvature and they have an equal radius on both sides.
The positive conjugate ratio ranges from 0.2 to 5.

focal point and principle axis of biconvex lens is shown in the image

Also read -

The formula for biconvex lens:

We know the formula for focal length is

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

Where f represents the focal length of the biconvex lens

u represents the object distance from the biconvex lens

v represents the image distance from the biconvex lens

The refraction of the spherical surface formula is given as

$\frac{1}{v}-\frac{1}{u}=(\frac{\mu_2}{\mu_1}-1)[\frac{1}{R_1}-\frac{1}{R_2}]$

Where 1 and 2 are the refractive indexes of the medium

R1and R2 are the radii of curvature of lens 1 and lens 2

Related Topics Link,

Making of the biconvex lens in the home:

Take and cut the cardboard with a diameter of 2.5 centimetres.
Place the cardboard on the water bottle and make its shape. Now cut the two different circles from the water bottle of the same radius of cardboard by using the scissors.
Paste the two circles such that the centre of the lens is not stuck together.
Now, this circle looks like a partial biconvex lens.

Uses and applications of the biconvex lens:

These lenses are used as condensing or magnifying lens
Objectives or magnifiers are made up of the biconvex lens
Imaging systems like microscope, telescope, monocular, binoculars, camera and so on utilizes the biconvex lens in their manufactures.
The biconvex lens is used in the burning glass.
The biconvex lens also plays an important role in image relays and is used in different optical industries.
The biconvex lens is used to produce the virtual image which is used to clear the defects in the human eye and real image in some photographic films and is also used in optical sensors.

In this article, we saw a detailed explanation of the biconvex lens, its working and its uses. Let us discuss some frequently asked questions asked in class 10, class 11 and class 12 related to the biconvex lens.
Also check-

Frequently Asked Questions (FAQs)

1. What is biconvex lens/give the biconvex definition/biconvex meaning.

The term ‘biconvex’ itself explains that the biconvex lens is made up of two convex lenses.

2. Who discovered lens and convex lens?

The lens is discovered by George Rober Carruthers and Pal Rudolph and also the Convex lens is discovered by Roger Bacon

3. What is biconvex shape?

Biconvex is curved at both sides.

4. Write down the difference between the convex lens and convex mirror.

There are two major differences between the convex lens and convex mirrors, the transparency of the convex mirror is opaque and the transparency of the convex lens is transparent. The reflection of light is the result of the convex mirror and the refraction of light is the result of a concave lens.

5. Write down the difference between the convex lens and concave lens.

The centre of the convex lens is thicker whereas the centre of the concave lens is thinner. For the convex lens, the edges are thinner whereas the edges of the concave lens are thicker. The convex lens is known as a converging lens as it converges the incident ray and the concave lens are known as a diverging lens as it diverges the incident ray. These are the major differences between the convex lens and concave lens.

6. What is double convex lens?

Lenses having the same radius of curvature on both the sides are called double convex lens.

7. Difference between the biconvex lens and double convex lens.

There is no big difference between the double convex and biconvex lens, as they are made up of the same type of lens. The only difference is the radius of curvature of the lenses used is different in the double convex lens whereas the radius of curvature of the lenses used is the same in the biconvex lens.

8. Give some uses and application of biconvex lens.

These lenses are used as condensing or magnifying lens
Objectives or magnifiers are made up of the biconvex lens
Imaging systems like microscope, telescope, monocular, binoculars, camera and so on utilizes the biconvex lens in their manufactures.
The biconvex lens is used to produce the virtual image which is used to clear the defects in the human eye and real image in some photographic films and is also used in optical sensors.
The biconvex lens is used in the burning glass.
The biconvex lens also plays an important role in image relays and is used in different optical industries.

9. List some of the properties of biconvex lens

The focal length of the biconvex lens is found to be in the positive axis

The focal length of the biconvex lens is found to be very shorter than the concave lens
The incident light converges in the biconvex lens.
The output images are found to be both real and virtual images, it depends on the focal length of the incident light beam.
To minimize the spherical aberration, coma and distortion, the biconvex lens is used in practice.
The biconvex lens is symmetrical as it is made up of two exact convex lenses with the same radii of curvature and they have an equal radius on both sides.