This topic accounts for approximately 9% of your exam marks.
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Ray diagrams, Snell's Law and critical angle calculations appear regularly.
Light
Light is part of the electromagnetic spectrum, so it is a transverse wave
The vibrations of the electric and magnetic fields that make up the wave are at right angles to the direction the light is travelling
Light can be reflected off a boundary and refracted through a boundary; both effects are covered in detail in the rest of this topic
Sound
Sound waves are longitudinal waves; the air particles oscillate back and forth along the same line that the wave is travelling along
Sound can also be reflected and refracted:
the reflection of a sound wave off a hard surface is called an echo
sound refracts when it crosses between media of different densities (for example, layers of warm and cold air, or air and water), bending its direction of travel
Why both bend
The same wave phenomena work for any wave type (water ripples, sound, light, microwaves, even seismic waves) because reflection and refraction depend on how a wave's speed changes when it meets a boundary, not on whether it is transverse or longitudinal