Wave Fundamentals and Key Definitions

Transverse waves are like the classic waves you'd see at the beach - the water moves up and down whilst the energy travels horizontally towards the shore. Think of wiggling a rope up and down; the wave travels along the rope even though you're moving it vertically.

Longitudinal waves work differently - here, the vibrations happen in the same direction as the energy transfer. Sound waves are perfect examples of this. When you speak, air particles get squashed together (compression) and spread apart (expansion) in the same direction the sound travels.

Every wave has measurable properties that you'll need to know inside out. Amplitude is simply how big the wave is - measured from the middle line to the peak. Wavelength is the distance between two identical points on consecutive waves (like peak to peak). Frequency tells you how many waves pass a point each second, whilst period is how long it takes to make just one complete wave.

Quick Tip: Remember the wave equation v = f × λ (velocity = frequency × wavelength). This formula appears constantly in exam questions, so make sure you can rearrange it confidently.

The electromagnetic spectrum arranges all electromagnetic waves by wavelength, from massive radio waves (about the size of buildings) down to tiny gamma rays smaller than atomic nuclei. Visible light, infrared, microwaves, X-rays, and ultraviolet radiation all fit somewhere on this spectrum. What's brilliant is they all travel at the same speed in a vacuum - the speed of light!