Difference WikiPhysics

Difference Between Mirror and Lens

Main Difference

The main difference between the Mirror and Lens is that Mirror is a single surface object that can reflect light, whereas Lens is a two-surface object that can refract light.

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Mirror vs. Lens

Mirrors form an image, and light bends through the lens. A mirror is a smoothly polished glass surface that forms an image of an object when light falls on it. On the other side, a lens is a transparent object with a spherical surface that may create both real and virtual images.

The mirror made up of glass and a highly polished metal placed behind it. On the other side, the lens made up of transparent plastic or glass. A mirror has a plane or spherical shape with a single surface while; a lens is with two surfaces that are curved outward or inward. So, due to a single surface, a mirror has a single focal point. On the other hand, as the lens has two refracting sides so, it has two focal points.

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The mirrors act on the principle of reflection, i.e., it works by reflecting the light incident on it. On the flip side, the lens acts on the principle of refraction, i.e., it works by refracting the light passing through it. A mirror that reflects 100% of light is known as an ideal mirror whereas, a lens that refracts 100% of light is called an ideal lens.

The mirror equation is used to make calculations related to the image formed by a mirror, i.e., 1/f = 1/v ₊ 1/u. On the other hand, the lens equation is used to make calculations related to an image formed by a lens, i.e., 1/f = 1/v ₋ 1/u — the mirror used in automobiles, houses, solar appliances, etc. On the flip side, the lens used in astronomy, medical, scientific industries, and for research purposes, etc.

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There are two main types of the mirror, i.e., concave mirror and convex mirror. On the other side, the lens has many types but, its two main types are concave lens and convex lens.

Comparison Chart

MirrorLens
A smoothly polished glass surface that forms the image of an object when light falls on it is known as a mirror.A transparent object with a spherical surface that may form both real and virtual images when light refracted through it is known as a lens.
Composition
Mirror made up of glass and a highly polished metal placed behind it.The lens made up of bent and transparent plastic or glass.
Shape
A mirror has a plane or spherical shape.A lens has curved or bent surfaces.
Number of Surfaces
It has a single surface.It possesses two surfaces.
Focal Point
As a mirror has a single surface, so it has a single focal point.The lens has two refracting surfaces, so it has two focal points.
Working Principle
The mirrors act on the principle of reflection.The lens acts on the principle of refraction
Ideal Condition
A mirror that reflects 100% of light is known as an ideal mirror.A lens that refracts 100% of light is called as an ideal lens.
Equation
The mirror equation to make calculations related to the image formed by a mirror is 1/f = 1/v ₊ 1/u.The lens equation to make calculations related to an image formed by a lens is 1/f = 1/v ₋ 1/u.
Types
Its three main types are a concave mirror, convex mirror, and plane mirror.The two main types of lens are a concave lens and a convex lens.
Uses
The mirror is used in automobiles, houses, solar appliances, etc.The lens is used in astronomy, medical, scientific industries, and for research purposes, etc.

What is Mirror?

A piece of glass polished from its back or with a highly polished metal placed behind it is known as a mirror. A mirror has a plane or spherical shape with a single surface. Due to its single surface, it has a single focal point, while plane mirrors are without a focal point. The mirror equation that used to make calculations related to the image formed by a mirror given as 1/f = 1/v ₊ 1/u

The mirror is used in automobiles, houses, solar appliances, etc. It works on the law of reflection. According to this law when light falls on a surface

  • The angle of the incident would be equal to the angle of reflection
  • All the rays lie in the same plane, i.e., normal ray, incident ray, and the reflected ray.

Types

  • Plane Mirror: It is a type of flat mirror. The plane mirror reflects the incident light rays in the same way as they fall on the mirror, i.e., angle of reflected ray is the same as the angle of incidence. Left to the right reversed image appears in a plane mirror without top-bottom vertical reversal while the distance and size of the object remain the same in reflection as it is in reality.
  • Concave Mirror: It does not have a flat reflective surface. Its surface is curved inward, just like the interior of a bowl. It has thicker edges as compared to the center and forms larger and upright images. Its example is the mouth mirrors that are used by dentists to form a magnified image of the teeth of the patient. They are also used to amplify the face of a person during shaving.
  • Convex Mirror: It is also without a flat reflective surface. Its surface bends or curves outwards, just like the outer surface of a bowl. It has a thicker middle portion as compared to its edges. This type of mirror produces an upright and smaller image as compared to the real object.

What is Lens?

A lens is a transparent object with a spherical surface that may form both real and virtual images when light refracted through it. A lens is with two surfaces that are curved outward or inward due to which it has two focal points.

The lenses are used in astronomy, medical, scientific industries, and for research purposes, etc. It works according to the law of refraction that is also called Snell’s law. Based on refractive indexes of the two media, this law describes how much a ray of light bends during its travel from one medium to another.

Flat, concave (curving inward), and convex (curving outward) surfaces combined in different ways to form different types of lenses. Convex surfaces used to converge rays of light that are passing through it. On the other hand, concave surfaces used to diverge the light rays that are passing through it.

The nature of the image that is formed by a lens is based on the nature of the lens and the position of the object. For example, a magnifying glass or a biconvex lens placed close to an object to view an enlarged, virtual, and upright image of the object. On the other side, the same lens used to form an inverted, real, and diminished image of an object that placed far away. The lens equation that used to make calculations related to an image formed by a lens is given as 1/f = 1/v ₋ 1/u.

Types

  • Concave Lens: It is thicker on the edges as compared to its middle portion. So, the rays that pass through this type of lens diverge from the focal point and form only smaller and virtual images. These types of lenses mostly used in TV projectors.
  • Convex Lens: This type of lens is thicker in the middle as compared to its edges. So, its surface is bent outwards from the center. Convex lens converges light into a single point that travels through it. So, after passing through a convex lens, the parallel rays of light join at the same point. The image that is formed by a convex lens depends on the position and distance of the object. This type of lens is used in telescope, binoculars, and magnifier, etc.

Key Differences

  1. A smoothly polished glass surface that forms the image of an object when light falls on it is known as a mirror, whereas a transparent object with a spherical surface that may form both real and virtual images when light refracted through it is known as a lens.
  2. A mirror made up of glass and a highly polished metal placed behind it. On the other hand, the lens made up of bent and transparent plastic or glass.
  3. The mirror has a single surface. On the flip side, the lens has two surfaces.
  4. A mirror shows a plane or spherical shape; conversely, a lens has curved or bent surfaces.
  5. As a mirror has a single surface, so it has a single focal point. On the other side, as the lens has two refracting sides so, it has two focal points.
  6. The mirrors act on the principle of reflection. It works by reflecting the light incident on it. On the other hand, the lens acts on the law of refraction, i.e., it works by refracting the light passing through it.
  7. A mirror that reflects 100% of light is known as an ideal mirror, while a lens that refracts 100% of light is called an ideal lens.
  8. The mirror equation to make calculations related to the image formed by a mirror is 1/f = 1/v ₊ 1/u. On the other hand, the lens equation to make calculations related to an image formed by a lens is 1/f = 1/v ₋ 1/u.
  9. The two main types of mirrors are a concave mirror and a convex mirror. On the flip side, the two main types of lens are the concave lens and a convex lens.
  10. The mirror is used in automobiles, houses, solar appliances, etc. On the other side, the lens is used in astronomy, medical, scientific industries, and for research purposes, etc.

Conclusion

The above discussion summarizes that the Mirror is a smoothly polished glass surface that forms the image of an object by working on the principle of reflection. On the other side, a Lens is a transparent object with a spherical surface that may form both real and virtual images by working on the principle of refraction.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss