What Is Refraction? What Is Refractive Index?

Last Updated on Mar 14 2024

Refraction is one of the most frequently observed phenomena; without it, our world as we see it now would be a haze.

Refraction is the bending of light as it passes from one transparent medium to another due to the density difference between the two mediums. This bending of light makes it possible to have prisms, rainbows, and optical instruments such as lenses and magnifying glasses. Our eyes also rely on refraction to focus light into our retina.

How Does It Work?

Light will refract or bend when it travels at an angle into a medium with a different optical density, known as its refractive index. The change in speed causes the change in direction, so if a medium causes the traveling light to slow down or speed up, the light will bend more.

The degree of refraction will be more noticeable if the light enters the medium at a greater angle.

The angles are measured by drawing an imaginary dotted line known as the normal 90 degrees to the surface of the two mediums. If light enters a medium with a lower refractive index, the light will bend away from the normal line and speed up. If it enters a medium with a higher refractive index, it bends towards the normal line and slows down.

What Is the Refractive Index?

The refractive index is dimensionless and describes how fast light travels through a medium and is also known as the index of refraction. The refractive index is the ratio of the speed of light in a medium(v) to the speed of light in a vacuum(c). If the refractive index of a medium is represented by n, the following formula can be used to calculate it:    n=c/v

If a light ray travels from a medium with a higher refractive index to another with a lower refractive index, it bends toward the normal; otherwise, it bends away from the normal.

Laws of Refraction

What Are the Different Types of Refraction?

Refraction in Spectrum

Refraction in the spectrum describes how white light travels through a prism, causing each color to refract at a different angle. As a result, a prism can be used to depict the VIBGYOR colors in the spectrum. Light is made up of waves, which explains why these colors appear when they pass through the prism.

Because the wavelengths of red light and violet light differ, their refractive indexes differ, with red light having a longer wavelength than violet light. The refraction of light in the spectrum demonstrates that white light is composed of the colors of the Rainbow.

Types of Refraction in our Daily Lives

Applications of Refraction

Refraction is useful in both optics and technology. However, it is primarily determined by the type of spherical lens used, whether convex or concave. A convex lens, also known as a converging lens, is the lens used to manufacture magnifying glasses. It’s thicker in the center and thinner around the edges. A concave lens, also known as a diverging lens, is thinner in the center and thicker at the edges. Light is refracted outwards as it enters a concave lens and then again as it exits it. 

Frequently Asked Questions (FAQs)

What is the difference between reflection and refraction of light?

Light reflection occurs when light bounces off a medium. The angle of incidence equals the angle of reflection if the medium has a smooth surface. Light refraction is the change in the direction of light as it travels from one medium to another.

How do you define light?

Light is a type of energy that allows us to see. It comes from a source and bounces off objects our eyes perceive, and our brain processes this signal, allowing us to see.

When is the refraction of light not possible?

Refraction of light is not possible when the incident light is perpendicular to the boundary.

What is an example of light refraction?

A rainbow is an example of refraction because the sun’s rays bend through raindrops, resulting in the rainbow. If you’ve ever noticed that the water’s surface appears shallower than it actually is, it is due to light reflection as it travels from water to air before entering our eyes.

Conclusion

Refraction is the bending of light as it travels from two mediums of different densities. The refractive index describes how fast the light travels between the two mediums. Refraction has been applied to both optics and technology, making it possible to make optical instruments such as microscopes, telescopes, and lenses.

It is seen in our everyday life, and the reason we can physically see it is also thanks to refraction. Otherwise, it would be a blur. The twinkling stars, rainbows, mirages, and optical illusions are all due to the phenomena of refraction.

• See also: Refraction vs Diffraction: What’s the Difference?

Featured Image Credit: Billion Photos, Shutterstock