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(a) describe and distinguish between progressive

longitudinal and transverse waves

Progressive waves are waves which travel through a material or a vacuum and transfer energy from one point to another

In longitudinal waves, the oscillations are parallel to the direction of travel, for example, sound waves

In transverse waves, the oscillations are perpendicular to the direction of travel, for example electromagnetic waves

Waves can be mechanical (meaning they need a substance for their transmission) or electromagnetic (meaning they can travel through a vacuum)

(b) define and use the terms displacement,

amplitude, wavelength, period, phase

difference, frequency and speed of a wave

Displacement is the distance and direction of a vibrating particle in a wave from it's undisturbed position

Amplitude is the maximum displacement of any particle in a wave from it's undisturbed position

Wavelength is the distance between two consecutive points on a wave which are in phase with each other. Or the distance between two consecutive crests/ troughs

Period is the time taken for one complete wave to pass a fixed point. Or the time taken for one complete oscillation of a particle in the wave

Phase difference between the two vibrating particles in a wave is the fraction of a cycle between the vibrations of the two particles. A full cycle is 2 pi

Frequency is the number of complete waves passing a fixed point per second. Or the number of complete oscillations per second of a particle in the wave

(c) derive from the definitions of speed,

frequency and wavelength, the wave

equation v = fλ

(d) select and use the wave equation v = fλ

(e) explain what is meant by reflection, refraction

and diffraction of waves such as sound and

light