Wave Calculations

• There are different physical parts of a wave.• Amplitude, Crest, Trough, Wave Length

Wave Speed

• But what if I want to know how long it takes for a wave to travel or how many waves go by in a second? Do I have to stand there and count waves?

• Answer: NOPE! We can use math.

Period

• Period is how long it takes for one wave length to pass by or one full rotation of a particle.

• Period is represented by the symbol “T”.

• It is measured in seconds.

Frequency

• Frequency is how many waves can pass by in a given time frame. (How rapidly the vibrations occur).

• The symbol for Frequency is:

• It is measured in hertz (Hz). 1 Hz is 1 wave per second.

Frequency and Period Equation

• The more waves per second the faster each wave is traveling. That means Frequency and the Period are related.

• Frequency = 1/Period• Written as symbols:

Wave Speed

• You already know the formula for speed:

• So lets apply that to waves:– Wave speed = wave length / Period– In symbols:

Wave Speed

• But there is another way….

• Since the frequency is 1/T I can multiply the wave length times the frequency.

• Wave speed = • In symbols:

The Medium Matters

• The speed of a wave depends upon the medium it is traveling through.

• State of the medium, the type of medium and the temperature of the medium all matter.

The Type of Wave Matters

• The type of wave also determines the speed.

• Electromagnetic waves do not need a medium.

• All electromagnetic waves travel through a vacuum at c = 2.99792458 x 108 m/s.

Put them in a medium and they get bounced around.

Doppler Effect

• How a wave sounds (pitch) depends upon the frequency.

• Meaning the more waves pass by in a second the higher the pitch.

• This can be created by the Doppler effect.