2D and 3D Wavefronts

The next set of lessons looks at different kinds of wavefronts. Recall electromagnetic radiation from the previous lessons as well as different wave properties from transverse waves and longitudinal waves from the tutorial on mechanical waves. The following provides a summary of the topics covered in the next set of lessons.

• Definition of a wavefront

  Wavefronts are imaginary lines joining waves that are in phase.

• Huygen's principle

  Every point of a wave front serves as a point source of spherical, secondary waves. After a time t, the new position of the wave front will be that of a surface tangent to the secondary waves. This principle describes how waves propagate and how waves interfere with other waves.

• Definition of diffraction

  Diffraction is the ability of a wave to spread out in wavefronts as the wave passes through a small aperture or around a sharp edge. This is most easily seen with water waves in a ripple tank. As the water waves reach the slit or barrier they spread out into the calm area beyond the slit or barrier.

• Sketching the diffraction pattern for a slit

  In this topic, you are shown how to make simple sketches of diffraction patterns as well as learning about how waves interfere to form crests and troughs.

• The degree of diffraction and calculating this

  The degree of diffraction is proportional to the wavelength and inversely proportional to the width of the slit. The degree of diffraction is explored in more detail and some simple calculations of this are given.

• Diffraction of light and how this relates to the wave nature of light

  All the above concepts are applied to how light diffracts when moving through a single slit. Light shone through a diffraction grating emphasises the wave nature of light.

You have learnt about the basic properties of waves before, specifically about reflection and refraction. In the next set of lessons, you will learn about phenomena that arise with waves in two and three dimensions: diffraction. We will also build on interference which you have learnt about previously but now in more than one dimension.