# Wave diagram conventions

• Absorption: Absorption is the process by which a material absorbs some or all of the energy of light. This can be represented by a decrease in the amplitude of the wave as it passes through the material.
• Brewster’s angle: Brewster’s angle is the angle of incidence at which light is polarized when it reflects off a surface. This can be represented by a line or an arrow indicating the direction of polarization of the reflected light.
• Diffraction: Diffraction is the bending of waves around obstacles or through narrow openings. Diffraction can cause waves to spread out and interfere with each other.
• Dispersion: Dispersion is the phenomenon where the speed of light varies with its frequency or wavelength. This can be represented by a graph showing the variation of the refractive index with wavelength or frequency.
• Frequency: Frequency is the number of wave cycles that occur in one second. It is typically represented by the symbol f and is measured in Hertz (Hz).
• Huygens-Fresnel principle: The Huygens-Fresnel principle states that every point on a wavefront can be considered as the source of secondary spherical waves, and the sum of these waves determines the shape of the wavefront at a later time. This can be represented by drawing small circles around each point on a wavefront to represent the secondary waves.
• Interference: Interference is the interaction of two or more waves that meet at the same point in space and time. Interference can be constructive, where the amplitudes of the waves add up, or destructive, where the amplitudes of the waves cancel each other out.
• Phase: Phase is a measure of the position of a wave relative to a reference point in time. It is typically represented by the symbol ϕ and is measured in radians.
• Period: Period is the time it takes for one wave cycle to occur. It is the reciprocal of frequency and is typically represented by the symbol T and is measured in seconds.
• Phase velocity and group velocity: Phase velocity is the speed at which the wavefronts propagate, while group velocity is the speed at which the wave packet (a group of waves with slightly different frequencies) propagates. These can be represented by arrows showing the direction and speed of the wavefronts and wave packet.
• Polarization: Polarization is the orientation of the electric field of a wave in a particular direction. Polarization can be linear, circular, or elliptical. It is typically represented by an arrow or a symbol.
• Polarization plane: The polarization plane is the plane in which the electric field vector of a polarized light wave vibrates. This can be represented by a line or an arrow indicating the direction of the electric field vector.
• Reflection: Reflection is the bouncing back of a wave after it strikes a boundary between two media. This can be represented by the wavefronts reflecting off the boundary and changing direction.
• Refraction: Refraction is the bending of a wave as it passes from one medium to another with a different refractive index. This can be represented by a change in the direction of the wavefronts at the boundary between the two media.
• Scattering: Scattering is the process by which light is redirected in many directions as it passes through a medium with irregularities or particles. This can be represented by arrows indicating the directions in which the scattered light is going.
• Snell’s law: Snell’s law relates the angle of incidence and refraction of light at the boundary between two media with different refractive indices. This can be represented by a diagram showing the path of the incident and refracted rays and the angles of incidence and refraction.
• Standing waves: Standing waves are patterns that result from the interference of two waves of the same frequency travelling in opposite directions. They have nodes, where the amplitude of the wave is zero, and antinodes, where the amplitude is at a maximum. These can be represented by dashed lines or nodes and antinodes marked on a wave diagram.
• Wavefronts: Wavefronts are imaginary surfaces that represent the points of a wave that are in phase with each other. In a two-dimensional diagram, wavefronts are represented by lines that are perpendicular to the direction of wave propagation.
• Wavelength: Wavelength is the distance between two successive wavefronts of a wave. It is typically represented by the symbol λ and is measured in meter.
• Wavevector: Wavevector is a vector that represents the direction of wave propagation and the wavelength of the wave. It is typically represented by the symbol k and is measured in reciprocal meters (m⁻¹).