Waves (Transverse/Longitudinal/Waves/Waves Equation)

What are ripples on the surface of water an example of

Transverse waves

What are sound waves travelling in the air an example of

Longitudinal waves

What do all waves do

All waves transfer energy from one place to another

What do ripple waves transfer

Kinetic energy

What do sound waves transfer

Sound energy

What is Oscillations?

When a wave is moving up and down

What happens in transverse waves?

The oscillations are perpendicular to the direction of energy transfer(Basically oscillation is up and down but direction of energy transfer is sideways)

What are Longitudinal waves?

The oscillations are parallel to the direction of energy transfer

What do all Longitudinal waves require?

A medium to travel in

For both ripples on a water and sound waves in air what travels

It’s the wave that travels and not the water or the air

What is this an example of and what is it

It’s the amplitude of a wave where the maximum displacement of a point on a wave away from it’s undisturbed position

What is this an example of and what is it?

It’s the wavelength of a wave where the distance from one point on one wave to the equivalent point on the adjacent wave

How do we measure a wavelength in a longitudinal wave?

We measure from one compression to the next compression or from one rarefaction to the next rarefaction

What is Frequency and what’s the unit

Frequency is the number of waves passing a point each second

-The Unit of Frequency is the Hertz(Hz)

What is period

Period is the time(in seconds) for one wave to pass a point

How can you calculate period

Period = 1/Frequency

A wave has a frequency of 100Hz

Calculate the period of the wave

Period = 1/Frequency

Period = 1/100

Period = 0.01 seconds

How do you calculate frequency

Frequency = 1/Time(Seconds)

What is the wave speed

The wave speed is the speed at which the wave moves through the medium(ie speed at which energy is transferred)

How do you calculate wave Speed

Wave speed(Metres/Second) = Frequency(Hz) X Wavelength(Metres)

Just for help

A wave has a frequency of 10,000Hz and a wavelength of 2cm

Calculate the speed of the wave

2cm =0.02m

Speed of wave = 10000 X 0.02

Speed of wave = 200m/s

Describe the method to measure the speed of sound waves in air

1)Have two people separated by a distance of 500 metres

2)Person A is holding a pair of cymbals and Person B is holding a timer

3)Person B starts timing when she sees person A clash the cymbals together

4)Person B then stops timing when she hears the sound of the cymbals clashing

5)Then calculate speed of sound waves by dividing distance travelled by the time taken

What is the problem of this experiment

Every person has different reaction times

How can we reduce this error

By having a large number of observers with timers then take all their results and discard any that are anomalous. We then calculate a mean value.

How can we reduce the problem of pressing the timer at the correct times

By increasing the distance between Person A and Person B

-The longer the distance the longer the time. This makes it easier to start and stop the timer at the correct times.

What are examples of Transverse waves

-Electromagnetic waves

-Ripples in water

-S-Waves

What are the examples of longitudinal waves

-Sound waves

-P-waves

-Pressure waves by repeated movements in l/g