In science, light rays are considered waves. These waves follow reflection and refraction laws that define their behavior, speed, and pattern. Refraction and reflection are both phenomena that govern the propagation of light.
The main difference between reflection and refraction is that in reflection, a light ray (or wave) goes back to the medium it is coming from after striking a plane with a change in direction. In refraction, the light ray passes through the plane into another medium, changing its speed and direction.
In this blog, we will discuss the two phenomena in further detail, understand them thoroughly, and point out the differences between the two.
What is Reflection?
Reflection is the alteration of a wavefront's direction at an interface between two different media so that the wavefront returns to the medium from which it came.
Common examples include the reflection of sound and light waves. In the case of reflection of light, the incoming ray striking the surface is known as the incident ray, and the bounced back ray is called the reflected ray. Based on the nature of the wave's striking plane, reflection can be categorized into two types: regular reflection and irregular reflection.
A simple example of reflection is the image we see of ourselves in a mirror.
What is Refraction?
Refraction in physics is the redirection of a wave as it travels through one medium and then another. A change in the medium or the wave's speed might result in a redirection.
The new energy of a refracted wave depends on the change in the original speed and direction of the wave.
Although refraction of light waves is the most commonly observed phenomenon, refraction may also occur with sound waves and water waves.
We see the refraction of light frequently in daily life. For example, when you are underwater, objects might seem closer than they are. It is the foundation upon which optical lenses are built, enabling devices like glasses, cameras, binoculars, microscopes, and the human eye. Rainbows and mirages are just two examples of natural optical phenomena caused by refraction.
Differences between Reflection and Refraction
Based on laws
Different laws govern refraction and reflection:
- The incident ray, the reflected ray, and the normal of the reflection surface lie in the same plane.
- The normal makes the same angle with the reflected and the incident ray.
- The reflected and incident rays do not lie on the same side but in the opposite direction of the normal.
The law of refraction follows Snell's law, which states that:
The ratio between the sine of the angle of incidence and the sine of the angle of refraction is constant in any two-given medium. The incident ray, the refracted ray, and the normal ray all reside in the same plane at the interface of any two distinct media.
Based on surfaces
Reflection occurs from surfaces that do not allow light to pass through them. Thus, light has only one way to go, to get reflected back into the original medium. On the other hand, refraction occurs on transparent surfaces, i.e., they allow light to partially pass through them, resulting in a change of direction and speed.
Based on the speed of light
When the reflection of a light wave occurs, there is no change in the speed of light, whereas when the same light wave undergoes refraction, its speed changes.
Based on the angles of light waves
The angle of reflection and incidence is the same in the case of reflection. In refraction, the incidence angle and the reflection angle are not the same.
Comparison Table: Reflection Vs Refraction
|Description||When light strikes a smooth surface, reflection occurs when the light bounces back||Refraction is the bending of light beams as they pass through different lines|
|Nature of surface||Shiny surfaces||Transparent surfaces|
|Types||Two types: regular and irregular||It is only one type|
|Occurrence||It occurs in mirrors||It occurs in lenses|
|Speed of light||The speed of light after reflection is unchanged||The speed of light after refraction changes|
Similarities between Reflection and Refraction
The fact that light waves strictly follow both reflection and refraction is their most significant similarity. Other than that, we see the criteria for the incident ray, reflected ray, and refracted ray are mentioned in the laws of reflection and refraction. In both reflection and reflection, the incident ray, the reflected ray, and the normal ray all lie in the same plane.
What distinguishes a reflected beam from a refracted ray?
Refraction and reflection of light are easily distinguished from one another. As the waves break off the surface, the light beam that hits the plane in reflection travels back to its original source or medium. But when there is refraction, the waves pass through the surface, changing their direction and speed.
What are some examples of reflection and refraction?
Examples of reflection and refraction could be found from day to day life. They include:
1. Plane mirrors (reflection)
2. Shining surface (reflection)
3. A glass bottle of oil (refraction)
4. Lens (refraction)
What type of mirror is used in vehicle headlights, and why?
A concave or converging mirror is utilized in the headlights of automobiles because it has a "reflection surface which recesses inward." When an item is placed in its focus region, it forms an image at infinity, which is utilized to concentrate light. Reflectors like these concave mirrors are employed in automobiles.
Both refraction and reflection help in understanding the behavior of light. Scientists use it to study various laws of nature, the movement of planets, and various astronomical phenomena. It also helps in studying phenomena like the formation of images in the mirror, rainbows in the sky, sunsets, capturing photographs, etc. These are extremely helpful in the development of science and technology.