Wavefronts and Wavelets


According to this theory, a source of light sends out disturbance or waves in all directions.  The wavefront at any instant of time is defined as the locus of vibrating particles in medium travelling in some phase at that instant.

Depending upon the shape of sources and its distance from the observer, wave front is further divided into three types:

Different types of wavefronts

1. Spherical wave front: If the source of light is point source, then the locus formed at  any instant is called the spherical wave front.

We know, $$ \text{Velocity} = \frac{\text{Distance (d)}}{\text{Time (t)}}$$

For light, V =  C


$$C =  \frac{d}{t}  $$

$$\therefore d = ct$$

This is the radius of wavefront at any instant of time t.

2. Cylindrical wavefront: If the source of light is linear in shape, then the locus formed at any instant is called cylindrical wavefront.

3. Plane wavefront: If the source of light is in infinite distance, then the wavefront formed is called plane wavefront.


The new spherical wave originating from wavefront of the wave which travels with the speed of wave at that medium  is called wavelet.

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One Response to “Wavefronts and Wavelets”

  1. Tirtharaj Dulal

    Sir, The notes you provide here are really much helpful to me..
    Thank you sir.