Refraction and Dispersion of Light through a Prism

Edited By Vishal kumar | Updated on Sep 24, 2024 04:05 PM IST

What is prism in physics? Refraction of light:

When a ray of light travels obliquely from one clear medium to another, it deviates from its original course. Refraction is the term for the deviation of a light ray. The variation in the velocity of light in the different mediums causes refraction. In a rarer media, light travels faster, while in a denser medium, it travels slower. There are two laws of refraction that govern light refraction.

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What is prism in physics? Refraction of light:
What is meant by dispersion of light by prism? What is dispersion of light class 10?
Relation between refraction and dispersion:

$Refraction and Dispersion of Light through a Prism$

Refraction and Dispersion of Light through a Prism

First law of refraction
Second law of refraction

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First law of refraction:

In the same plane as the incident ray, the refracted beam of light, and the normal to the refracting surface.

Second law of refraction:

The ratio of the refractive indices of the two media is equal to the sine of angle of incidence as well as sine of angle of refraction. Snell's law is another name for this law.

sin i sin r =21

The refractive index tells us how quickly or slowly light moves through a medium. The ratio of speed of light in vacuum (c) to speed of light in that medium is the refractive index of that medium (v).

=cv

In general, 12=speed of light in medium 1speed of light in medium 2

If i is the incidence angle and r is the refraction angle, then

sin i sin r =constant

The refractive index of the second media in relation to the first medium is called this constant. It is generally represented by the Greek letter 12

If the refractive index of a medium is high, speed of light in that medium is low, as well as if refractive index of medium is low, the speed of light in that medium is high.

The refracted beam is bent away from the normal drawn to the interface as light moves from denser medium into rarer medium.

The refracted ray is bending towards normal drawn to interface when light moves from a rarer medium into a denser material.

$Second law of refraction$

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What is meant by dispersion of light by prism? What is dispersion of light class 10?

Dispersion of light definition: The phenomenon of dispersion happens when a wave's phase velocity varies with its frequency. Dispersion media are media that have this attribute in common. The term "chromatic dispersion" is frequently used for clearness. Although the term is most commonly associated with light and other electromagnetic waves, it can also refer to any type of wave motion, such as acoustic dispersion in the case of sound and seismic waves, gravity waves, and telecommunication signals travelling along transmission lines or optical fibre. Dispersion results in a loss of kinetic energy due to absorption on a physical level.

Refraction of light through prism:

Refraction is the curving of light as it travels from one medium to another. When a beam of light passes through a glass prism, for example, it refracts both entering and exiting the prism.

Dispersion of light through prism:

The degree to which light refracts is determined by the wavelength of the light. Because each light wave has a different wavelength, it will deviate in different ways. White light is made up of several wavelengths of light (colours). Violet, indigo, blue, green, yellow, and red are dispersion of light examples of these colours. The maximum wavelength is red, while the lowest is violet. The variation in the path of light is dependent on the wavelength. The least deviated light is red, whereas the most deviated light is violet. When white light passes through a prism spectrum of seven hues appears, indicating that white light is made up of seven different colours. Prism just serves as a conduit for the dispersion of light in the seven primary hues. When light strikes the prism, refraction occurs. These deviated colours have distinct wavelengths and frequencies, and they deviate differently at different angles due to the prism's velocity differential. As a result, the colour red deviates the least because it has the longest wavelength, while the colour violet deviates the most because it has the shortest wavelength.

Dispersion of light through prism

Relation between refraction and dispersion:

Any bending of waves caused by a change in speed is referred to as refraction. A wave is said to be refracted when it travels through different depths. The frequency dependence of refraction is referred to as dispersion. When light is refracted by a prism, dispersion refers to how much the higher frequency light bends.

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Refraction of a composite light-Dispersion of light:

We know that the sun is the fundamental and natural source of light. A monochromatic source is one that produces only one colour of light. A composite light source, on the other hand, creates white light that incorporates light of various colours. Sunlight is a composite light made up of a variety of colours and wavelengths. A mercury vapour lamp is another example of a composite source. When a white light is refracted through a glass prism, what do you see?

When a beam of white or composite light passes through a transparent medium like glass or water, it splits into its component colours. Dispersion of light is the term for this phenomena.

Spectrum refers to the colour bands that make up a spectrum. Violet, Indigo, Blue, Green, Yellow, Orange, and Red are the hues that make up this spectrum. The acronym “VIBGYOR” stands for these colours. When white light is refracted by a transparent medium, why do we receive the spectrum? This is due to the fact that different coloured lights are bent at different angles. That means, the angle of refraction varies depending on the colour.

Red has the least angle of reflection while violet has the most. The angle of refraction is determined in terms of the medium's refractive index, according to Snell's law. As a result, the refractive index of the medium varies depending on the colour of the light.

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NCERT Physics Notes:

Frequently Asked Questions (FAQs)

1. Light travels from rarer medium to denser medium. The angles of incidence as well as refraction are 45oand 30o. Calculate refractive index of second medium with respect to first medium.

The angle of incidence, i=45o

The angle of refraction, r=30o

To find the refractive index of the second medium with respect to the first medium:

Refractive index, 12=sin i sin r

=sin 45o sin 30o =1 212

=2=1.414

2. What is refraction?

3. What is dispersion?

The phenomenon of dispersion happens when a wave's phase velocity varies with its frequency. Dispersion media are media that have this attribute in common. Dispersion results in a loss of kinetic energy due to absorption on a physical level.

4. What is refraction of light through a prism?

The bending of light as it moves from one medium to another is known as refraction. For example, when a ray of light passes through a glass prism, refraction happens both when it enters and exits the prism.

5. What is the Difference between Light Dispersion and Light Refraction?

Any bending of waves caused by a change in speed is referred to as refraction. The production of refraction occurs when water waves travel over a range of depths and heights.

When we state that light is refracted by a prism, we are referring to dispersion, which means that there will be a higher frequency of light bending.

The bending of light is referred to as refraction, while the frequency dependence of light properties is referred to as dispersion.