General Properties of Waves

Something tells me, this chapter is going to be zen af.

Waves are the transfer of energy through oscillations in a medium or through space, characterized by properties like frequency, wavelength, and amplitude.

Waves transfer energy without transferring matter.
Simply, Waves carry energy without moving the stuff they pass through.

This means that they do not require matter to move.

Features of a wave

Term	Definition
Wavefront	An imaginary line connecting points of the same phase.
Wavelength	The distance between two consecutive wavefronts.
Frequency	The number of wavefronts passing a point per unit time.
Crest (peak)	The highest point of a wave.
Trough	The lowest point of a wave.
Amplitude	The maximum displacement from the equilibrium position.
Wave Speed	The rate at which the wave travels through a medium.

We will take a look at the above features in greather depth further along in this chapter.

Types of waves

There are two types of waves:

Transverse waves
Longitudinal waves

Transverse waves

A wave in which oscillations are at right angles to the direction of motion is called a transverse wave

In other words, the direction of vibration is perpendicular (at right angles) to the direction of wave motion.

Examples: Ripples on water, electromagnetic radiation

Longitudinal waves

A wave where the oscillations are parallel to the direction of motion is called a longitudinal wave.

In other words, the direction of vibration is parallel to the direction of wave motion.

Example: Sound waves

Waves Simulation

Here is a waves simulator. You can choose between water, sound, and light and adjust the amplitude and frequency across different mediums to obtain a range of results.

We highly recommend giving this a shot to further sharpen your understanding of waves.

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Transverse waveforms have peaks and troughs
Longitudinal waveforms have compressions and rarefactions

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Compressions are regions of high pressure in a longitudinal wave, while rarefactions are regions of low pressure.

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Wavelength is the shortest distance between the same point on two consecutive waves (e.g. the distance between two consecutive peaks)

Now, its time for some math. Let's take a look at the wave equation-

The wave equation

v =λ × f

Where:

v = velocity (m/s)
λ = wavelength (m)
f = frequency (Hz)

Reflection

Waves reflect off smooth, plane surfaces rather than getting absorbed

Angle of incidence = angle of reflection

Rough surfaces scatter the light in all directions, so they appear matte and unreflective Frequency, wavelength, and speed are all unchanged

Refraction

The speed of a wave changes when it enters a new medium

If the wave enters a more optically dense medium, its speed decreases and it bends towards the normal

If the wave enters a less optically dense medium, its speed increases and it bends away from the normal

In all cases, the frequency stays the same but the wavelength changes.

Diffraction

white ship on blue sea during daytime — Diffraction is observed in harbours with barriers

Waves spread out when they go around the sides of an obstacle or through a gap

The narrower the gap, the more the diffraction

The greater the wavelength, the more the diffraction

Frequency, wavelength, and speed are all unchanged

This is the end of this guide. Thank you so much for using IGCSE Pro!

Here's a lil song to celebrate the completed revision of this chapter-