We are customised to seeing the world around us with our eyes but we don’t usually ponder upon how the light interacts with our vision. In simple terms, an object is only visible to our eyes when light is reflected from its surface. For instance, you might not be able to see anything on entering a dark room but once you switch on the lights, everything will be visible. This simple phenomena of the light bouncing back after falling on an object is referred to as the reflection of light. Let’s explore more about this topic through this detailed blog.
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What is Reflection of Light?
To begin with, the reflection of light occurs whenever a ray of light falls on a smooth polished surface and bounces back. In other words, the ray of light approaching any surface results in the reflection of the light. Further, the ray of light which falls on the surface is known as Incident ray while the ray of light which gets reflected back is called Reflected ray. Also, if a perpendicular is to be drawn between the two rays on the reflecting surface, it is known as a Normal.
Incident Ray= It is the ray which falls on the surface
Reflected Ray= The ray which is reflected from the surface
Normal = Perpendicular on the polished surface
P= Point of reflection
i= Angle of Incidence
r= Angle of Reflection
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Laws of Reflection
After understanding the meaning of reflection, you must also understand its two imperative laws. Using these laws, the reflection of the incident ray on various surfaces like a plane mirror, water, metal surfaces, etc can be determined. For instance, if we consider a plane mirror, here are the laws of reflection:
- The incident ray, the normal and the reflected ray must lie in the same plane.
- The angle of incidence (i) = The angle of reflection (r).
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Types of Reflection
While exploring the basics of the reflection of light, it is also important to go through the different types of reflection. Whenever we change the basic elements or the form of basic elements involved in this phenomenon, the result also varies. Following are the main three types of reflection:
- Regular Reflection
- Diffused Reflection
- Multiple Reflection
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Regular Reflection can also be referred to as Specular Reflection and is simply understood by using a plane mirror. This mirror used for reflection of light is not the regular mirror we see around us, rather it is a glass which is heavily coated with a uniform layer of highly reflective material such as a powder. As it is coated, the surface totally reflects all the light which falls on it i.e, there is not much variation in both the angles of reflection at multiple points. Due to this minimal variation, we can say that all the haziness and the blurriness is completely gone.
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To explore the meaning of diffused reflection, let us consider reflective surfaces other than mirrors. The common surfaces which can be used for diffusion of light are comparatively rough as they are made up of different material than glass and contain some marks, scratches, dust or dents. All these things hamper the quality and brightness of reflection. Thus, the comparison of both the angles of reflection on such rough surfaces is completely distorted. In diffused reflection, the incident ray falls on different points and gets reflected in an entirely different direction and hence, we see non-shiny objects.
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For both regular and diffused reflection of light, a single mirror is used while when we take two mirrors, a single source of light can be reflected multiple times. This type of reflection is only possible when the intensity of the light becomes so low that we cannot see it. Infinite images will be formed in multiple reflections, as each image is the result of another image.
The number of images varies as per the angle between two mirrors. If we decrease the angle, the number of images get increased. The number of images becomes infinite when the angle between the two mirrors is zero i.e, they are parallel. Here is a formula to calculate the number of images for diffused reflection of light:
A spherical mirror, whose reflecting surface is curved inwards, that is, faces towards the centre of the sphere, is called a concave mirror. A concave mirror can be compared to the inside of the spoon. Concave mirrors are the reflecting objects that are used in reflecting telescope.
A spherical mirror whose reflecting surface is curved outwards, is called a convex mirror. A convex mirror can be compared to the outside of a balloon. A convex mirror is used as a rear view mirror and for security purposes.
A number of parallel rays hit a convex mirror, they reflect outwards and travel directly away from an imaginary focal point (F).
Scattering of Light
When light hits very small gas particles or water droplets or even dust particles, it scatters the light. The amount of scattering of the light depends on the wavelength of light and the size of the particle. Light on the sky is filled with all the colours of the rainbow i.e. VIBGYOR. So, the question is ‘Why is the Sky Blue?’
It is because light hits different particles in the atmosphere and it scatters in all directions. Since blue has a smaller wavelength than Red, it is scattered more than red. That is why the sky looks blue.
Examples of Reflection of Light in daily life
Some of the most interesting examples of reflection of light in daily life are:
The Blue Sky is because light hits different particles in the atmosphere and it scatters in all directions. Since blue has a smaller wavelength than Red, it is scattered more than red. That is why the sky looks blue.
- The Sunset is Red because when the sunset happens, the sky has already scattered most of the blue light as it has travelled around the atmosphere since the day. So, the red light dominates during a Sunset.
- Clouds look White because the cloud’s water droplets are much larger than the wavelength of light. So, all the colours get scattered in different directions to create white colour.
Light Reflection and Refraction
Light Reflection and Refraction are two different properties of light. The major difference between the two is:
The reflection of light occurs whenever a ray of light falls on a smooth polished surface and bounces back. In other words, the ray of light approaching any surface results in the reflection of the light.
The refraction of light occurs when a ray of light moves from one medium to another and it changes its direction of travel.
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Thus, we hope that this blog has helped you understand the meaning, types and laws of reflection of light. Preparing for competitive exams like GRE, GMAT, IELTS or SAT? Sign up for an online demo session with our Leverage Edu career and we will assist in creating the right preparation strategy as well as providing you with the required study material and exam tips to ace your test successfully