Notice in a slinky wave like the one below, coils do not actually move from one end of the spring to the other ( it just looks like they do.

In transverse waves particles move ____________ to wave direction.

**Worked Example 1 Up or down?**

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**Wave characteristics**

( = wavelength cm, m

*A* = amplitude cm, m

*f* = frequency (waves per second) s(1 or Hertz (Hz)

*T* = period (time for one wave) s

*v* = velocity cms(1, ms(1

**Wave speed**

If 3 waves of wavelength 5 m are produced every second, then the wave speed must be ___________ ms(1.

In general, if *f* waves of wavelength ( are produced every second, then the wave speed is

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**More wave equations**

**Worked Example 2 Wave speed**

Find the speed of a wave of period 0.2

s and wavelength 15 cm.

**Worked Example 3 Finding wavelength**

Find the wavelength of a water wave of frequency 20 Hz that moves with a velocity of 30 cms(1.

**Worked Example 4 Finding the period**

A series of 8 waves span a distance of 120 cm. If the speed of the waves is 5 ms(1, find the period of the waves.

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**THE NATURE OF LIGHT**

**Electromagnetic waves**

One useful model for light is the wave model. Light may be thought of as a burst of magnetic and electric fields travelling at right angles to one another. The word "wave" is used to describe not the path light takes (this is usually straight), but the varying strength of the fields. The...