# everything maths & science

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## Chapter summary

• A wave is formed when a continuous number of pulses are transmitted through a medium.

• A crest is the highest point a particle in the medium rises to.

• A trough is the lowest point a particle in the medium sinks to.

• In a transverse wave, the particles move perpendicular to the motion of the wave.

• The amplitude ($$A$$) is the maximum distance from equilibrium position to a crest (or trough), or the maximum displacement of a particle in a wave from its position of rest.

• The wavelength ($$λ$$) is the distance between any two adjacent points on a wave that are in phase. It is measured in metres (m).

• The period ($$T$$) of a wave is the time it takes a wavelength to pass a fixed point. It is measured in seconds (s).

• The frequency ($$f$$) of a wave is how many waves pass a point in a second. It is measured in hertz (Hz) or s−1.

• Frequency: $$f = \frac{1}{T}$$

• Period: $$T = \frac{1}{f}$$

• Speed: $$v = f·λ$$ or $$v = \frac{λ}{T}$$.

Table 1: Units used in transverse waves
 Physical Quantities Quantity Unit name Unit symbol Amplitude ($$A$$) metre m Wavelength ($$λ$$) metre m Period ($$T$$) second s Frequency ($$f$$) hertz Hz (s−1) Wave speed ($$v$$) metre per second m·s−1