The difference between mirror and lens lies in how light reflects when falls over their surface. When light interacts with any surface, mainly two things happen; Reflection and Refraction. The main difference between mirror and lens is that image forms by reflection, as the light falls on a mirror. In lens, the image is formed by refraction. Let us now understand more about the difference between mirror and lens by studying in detail.
What is Mirror?
The mirror is the piece of glass that is polished on one side and reflects light falling on it. The more polished, or shiny, the more light will “bounce off” it’s surface. One of the surfaces is typically coated with a metal amalgam, which reflects a clear image. In a mirror narrow beam of light that incides on its surface bounces in a single direction, without scattering.
What is Lens?
A lens is a combination of two prisms, sometimes base up or base down. It is a transparent optical medium that converges or diverges a light beam by working on the principle of refraction. The lens is simple or compound (a combination of many simple lenses).
Difference Between Mirror and Lens
Difference between Mirror and lens
ImportantDifference between Mirror and lens
| Parameter | Mirror | Lens |
| Definition | The mirror is glass with one side silvery backing produces an image by reflection on only one surface. | The lens is a transparent substance that produces images by refraction in any surface of the two surfaces. |
| Curvature | It can be plane or curved. | Always curved at one or two surfaces. |
| Law | Laws of reflection | Laws of refraction |
| Types | There are two types: concave and convex | There are six types of lenses. |
| Focal point | Plane mirror has no focal point | It has 2 focal points for each type of lens |
| Manufacture | From glass or metal | From glass or plastic |
| Uses | Mirror tiles, dressing table, periscope, camera, looking glass, solar cooker | Refraction unit, spectacle glass, flashlight, telescope, microscope |
We must learn in detail to find out more after studying the difference between mirror and lens.
Mirror
A mirror is a piece of glass or polished metal surface coated with a metal film that reflects light without diffusion and produces an image of an object when placed in front of it. It forms a specular reflection. A plane mirror gives a real-looking undistorted image, while a curved mirror may distort, magnify, or reduce the image in various ways.
Mirrors can be classified in many ways; including by shape, support and reflective materials, manufacturing methods, and intended application.
Principle
1) Plane surface mirror- When parallel beams of light are reflected on a plane surface, the reflected rays will be parallel too.
2) If the reflecting surface is concave, the reflected beams will be convergent, at least to some extent, and for some distance from the surface.
3) convex mirror- It will reflect parallel rays towards divergent directions.
Mirrors are usually manufactured by either polishing a naturally reflective material, such as speculum metal or by applying a reflective coating to a suitable polished substrate. Two types of coating are widely in use, silvering and dielectric coating. Mirrors are commonly used for personal grooming, rearview mirror, one-way mirrors and windows, signaling, projectors, solar power, telescope, sculpture, decors, etc.
Lens
It is a piece of glass or other transparent material with curved sides for concentrating or dispersing light rays. It has two opposite surfaces either both curved or one curved and one plane. The curves are almost always spherical. A lens forms images of objects situated in front of it.
Lenses are classified according to their two surfaces as biconvex, plano-convex, concavo-convex (converging meniscus), biconcave, Plano concave, and convexo-concave (diverging meniscus).
Principle
” Different speed of light in the lens than in the surrounding air, causes refraction, i.e, an abrupt bending, of a light beam. It occurs both where the beam enters the lens and where it comes out from the lens into the air.”
During the manufacture of lenses, slabs of glass are cut with a glass saw or slitting disk or the pieces may be heated to softness and rolled to a round shape. Then it is pressed in a mold to the desired size and any required curvature of the surfaces. The surfaces are then ground, or lapped, to the final form.
Lenses are commonly in use in a magnifying glass, as spectacle correction for refractive error, projectors, camera, to generate solar energy, radio astronomy, etc.
FAQs about mirror and lens:
1) Why do telescopes use mirrors instead of lenses?
Ans- Most telescopes work by using curved mirrors to gather and focus light from the night sky. As mirrors are lighter, and they are easier than lenses to make a smooth combination.
2) Where is the concave lens useful?
Ans- Concave lenses cause light to spread out, resulting in a smaller image for the viewer. Concave lenses use includes eyeglasses and contacts, flashlights, peepholes, binoculars, telescopes, and in photography.
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