Mirror and Lens

The Lens is a transparent thick substance (made of glass or plastic) that bends light rays in a certain direction as they pass through it, either converging them to a specific point or diverging them away from it. A mirror is an item that allows us to view our own image as well as the image of the person in front of us. The difference between a mirror and a lens is the way light reflects as it passes through them. Reflection and refraction are the two major effects of light interacting with any surface. The major difference between a mirror and a lens is that a mirror creates an image by reflecting light. Refraction creates the picture in the lens.

What is Mirror?

The mirror is a piece of polished glass that reflects light falling on it on one side. The more polished or shining a surface is, the more light will “bounce” off of it. A metal amalgam is usually applied to one of the surfaces, which reflects a clear picture. A narrow beam of light colliding with the surface of a mirror bounces in a single direction without dispersing.

Principle

• Plane surface mirror- When parallel light beams are reflected on a plane surface, the reflected rays are also parallel
• If the reflecting surface is concave, the reflected beams will converge to some extent and for a certain distance from it
• convex mirror- Parallel rays will be reflected in diverse directions by a convex mirror

Mirrors are often made by polishing a naturally reflective material like speculum metal or putting a reflective coating to a properly polished substrate. Silvering and dielectric coating are the two most common forms of coating. Personal grooming, rearview mirrors, one-way mirrors and windows, signalling, projectors, solar power, telescopes, sculpture, and decors are all frequent uses for mirrors.

What is Lens?

A lens is made up of two prisms that are sometimes arranged base up or base down. It’s a transparent optical medium that uses the refraction principle to converge or diverge a light beam. There are two types of lenses: simple and complex (a combination of many simple lenses). It’s a curved-sided piece of glass or other transparent material used to concentrate or disperse light beams. It features two opposing curved surfaces, or one curved and one flat. Almost all of the curves are spherical. A lens creates pictures of the objects in front of it. Biconvex, plano-convex, concavo-convex (converging meniscus), biconcave, plano-concave, and convexo-concave lenses are characterised according to their two surfaces (diverging meniscus).

Principle

“Refraction, or a sudden bending of a light beam, occurs when the speed of light in the lens differs from the speed of light in the surrounding air. It happens when the beam enters the lens as well as where it exits the lens into the air.” Slabs of glass are cut with a glass saw or slitting disc during the manufacturing of lenses, or the pieces may be heated to softness and rolled to a circular form. Then it’s pressed into a mould to get the necessary size and any required surface curvature. After that, the surfaces are ground or lapped to their final shape. Magnifying glasses, spectacle correction for refractive error, projectors, cameras, solar energy generation, and radio astronomy all require lenses.

Difference Between Mirror and Lens

Parameter	Mirror	Lens
Definition	The picture is created by reflection on only one surface of the mirror, which is made of glass with a silvery backing on one side	The lens is a transparent material that generates pictures by refraction on any of the two surfaces
Curvature	It can be either flat or curved	One or two surfaces are always curved
Law	Laws of reflection	Laws of refraction
Types	Concave and convex are the two kinds	There are six different kinds of lenses
Focal point	There is no focus point in a plane mirror	It has two focus points for each lens type
Manufacture	Fabricated from glass or metal	Fabricated from glass or plastic
Uses	Mirror tiles, a periscope, a camera, a looking glass, and a solar oven	A refraction unit, a pair of spectacles, a flashlight, a telescope, and a microscope

The distinction between Mirror and Lens can be better appreciated by comparing their sign conventions and image formations. We’ll start with their sign conventions, then go on to the ray diagram of objects in various places in both the mirror and the lens.

Conclusion

The picture of whatever is placed in front of it is created using mirrors and lenses. The nature of the picture might vary depending on the position of the item, i.e. it can be real or virtual. A lens is made of glass or plastic, while a mirror is generally made of glass or metal.