Sradha

What Is Refraction?
Refraction is the bending of a wave when it passes from one medium to

another. The bending is caused due to the differences in density
between the two substances.
Defining Refraction
“Refraction is the change in the direction of a wave passing from one medium to
another.”
Refraction of light is one of the most commonly observed phenomena,
but other waves like sound waves and water waves also experience
refraction. Refraction makes it possible for us to have optical
instruments such as magnifying glasses, lenses and prisms. It is also
because of the refraction of light that we are able to focus light on our
retina.
Causes of Refraction
1.Change of Speed Results in Change in Direction
A light ray refracts whenever it travels at an angle into a medium of different
refractive indices. This change in speed results in a change in direction. As an
example, consider air travelling into water. The speed of light decreases as it
continues to travel at a different angle.
Laws of Refraction of Light
Laws of refraction state that:
•The incident ray refracted ray, and the normal to the interface of two media at the point of incidence all lie on the
same plane.
•The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant. This is also known as
Snell’s law of refraction.
What IsSin i/ sin r=Index?

the Refractive constant
The refractive index, also called the index of refraction , describes how fast light travels through the material.
The refractive Index is dimensionless. For a given material, the refractive index is the ratio between the speed of light in a vacuum (c) and the speed o
f light in the medium (v). If the refractive index for a medium is represented by n, then it is given by the following formula:
Based on the refractive index of the medium, the light ray changes its direction, or it bends at the junction separating the two media. If the
light ray travels from one medium to another of a higher refractive index, it bends towards the normal, else it bends away from the normal.
n=cv
Refraction of Light in Real Life
•Mirage and looming are optical illusions resulting from refraction of light.
•A swimming pool always looks shallower than it really is because the light coming from the bottom of the pool bends at the surface due to refraction of
•Formation of a rainbow is an example of refraction as the sun rays bend through the raindrops resulting in the rainbow.
•When white light passes through a prism it is split into its component colours – red, orange, yellow, green, blue and violet due to refraction of light.
Applications of Refraction of Light

Refraction has many applications in optics and technology. A few of the prominent applications are listed below:
•A lens uses refraction to form an image of an object for various purposes, such as magnification.
•Spectacles worn by people with defective vision use the principle of refraction.
•Refraction is used in peepholes of house doors, cameras, movie projectors and telescopes
What is Total Internal Reflection?
Total internal reflection is defined as:
The phenomenon which occurs when the light rays travel from a more optically denser medium to a less
optically denser medium.
Consider the following situation. A ray of light passes from a medium of water to that of air. Light ray will be refracted at the
junction separating the two media. Since it passes from a medium of a higher refractive index to that having a lower refractive index, the refracted light ray bends
away from the normal.
At a specific angle of incidence, the incident ray of light is refracted in such a way that it passes along the surface of the water. This particular angle of incidence is
called the critical angle
Here the angle of refraction is 90 degrees. When the angle of incidence is greater than the critical angle, the incident ray is reflected back to the medium. We call this
phenomenon total internal reflection.
Total internal reflection n1n2=sinrsini

Critical angle, θ sinθ=n2n1
What are the Conditions of Total Internal Reflection?
Following are the two conditions of total internal reflection:
•The light ray moves from a more dense medium to a less dense
medium.
•The angle of incidence must be greater than the critical angle.
Examples of Total Internal Reflection
Diamond:
When the incident ray falls on every face of the diamond such
that the angle formed, the ray is greater than the critical angle.
The critical value of the diamond is 23°. This condition is
responsible for the total internal reflection in a diamond which
makes it shine.
Mirage:
It is an optical illusion that is responsible for the appearance of
the water layer at short distances in a desert or on the road.
Mirage is an example of total internal reflection which occurs
due to atmospheric refraction.
Optical Fibre:
When the incident ray falls on the cladding, it suffers total
internal reflection as the angle formed by the ray is greater than
the critical angle. Optical fibres have revolutionised the speed
with which signals are transferred, not only across cities but
across countries and continents making telecommunication one
of the fastest modes of information transfer. Optical fibres are
also used in endoscopy.
Conclusion:
The main purpose of the topic is to state the world about the
phenomenon of every cycle which including air light water.
we daily coming across many thing which are un noticeable by
us.
Every thimgs has its own purpose and consequences which
humans should not play with it is good to increase the curiosity
without disturbing the nature
Now a days pollution is the main causes which we cannot solves
so easily thus for which environmental right should be raise
Bibliography
• https://byjus.com/physics/total-internal-reflection/#:~:text=Asked%20Questions%20%E2%80%93%20FA
Qs-,What%20is%20Total%20Internal%20Reflection%3F,a%20less%20optically%20denser%20medium
.
• https://en.wikipedia.org/wiki/Total_internal_reflection.
• https://www.vedantu.com/physics/total-internal-reflection

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What Is Refraction?

Refraction is the bending of a wave when it passes from one medium to

What IsSin i/ sin r=Index?

Applications of Refraction of Light

Total internal reflection n1n2=sinrsini

Examples of Total Internal Reflection

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