Reflection, Refraction And Time Period

Light travels in the form of a wave and is the source of energy that can be seen through the naked eyes. It is also known as visible light since the light falls under the visible spectrum having wavelengths in the range of 400–700 nanometers. Light is electromagnetic radiation with a certain portion of the electromagnetic spectrum. Visible light is a part of the vast electromagnetic spectrum. In the vacuum state, the electromagnetic radiation travels at the speed of light. The speed of light is found to be a constant and is given by c = 2.99792458 x 10^8 m/s.

Let us know how the wave propagates and also about what is time period of the light?

Light propagates in a wave format. In the sinusoidal wave, a periodic motion of the wave is witnessed.

From the figure above, T represents the time period and is given by T = 1/f.

The time period is the time consumed between the arrival of 2 consecutive crests or troughs at a certain location. The period is represented as T in the figure above. The period of a wave is given in seconds.

The propagation of light gives a clear picture in which an electromagnetic wave shifts its energy from one point to another. When light passes from one medium to another various process affects the propagation of light like:

  • Reflection
  • Refraction

Transmission of light varies from one medium to another. Transmission of light varies from glass to water. The transmission of the light differs from a solid to liquid.

Now let us make an attempt to know what is refraction and reflection of light.

When the light changes direction or bends as it passes through the boundary between one media to another, it is known as refraction. Index of refraction is defined as the ratio of the speed of light in a vacuum to the speed of light in the medium. It is given by,

n = c / v

Light waves are refracted when it passes the boundary of the transparent medium into another. The speed of light is noted to be different in each media. Refraction of light at the interface between two media of different refractive indices is given below.

The phenomenon in which the light beam rebounds after hitting a surface is known as reflection. The light beam that strikes the surface is called the incident ray and the reflected light beam that leaves the surface is known as the reflected ray. The process is explained in the figure below.

Law of reflection is given by θi = θr


θi = incident ray

θr= reflected ray

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