Physics: P12 - Wave Properties

What can waves be used for?

\-Radio

\-Sound

\-Microwaves

Wavelength

The distance between two peaks

Amplitude

The maximum displacement of a point of a wave from its rest position

Frequency

Number of waves passing a fixed point every second (Hz)

Transverse waves

Oscilations at right angles to the direction of energy trasnfer

Longitudinal waves

Oscillations parallel to direction of travel

Examples of transverse waves

\-Light waves

\-Microwaves

\-Radio waves

Examples of longitudinal waves

\-Sound waves

\-Ultrasound waves

\-Seismic P Waves

Equation for period of a wave

1/Frequency

What is a period of a wave?

Time taken for each wave to pass a fixed point

How is the period of wave related to its frequency?

As the frequency of a wave increases, the period decreases

What is wave speed?

How far the wave travels every seccond?

Wave speed equation

Frequency x Wavelength

What happens when a wave crosses a boundary between two different materials?

It changes directions

What is a sound wave?

A longitudinal wave that creates sound

Refraction

The wave changes direction when going through something

Reflection

Wave bounces off a surface

Where are waves reflected?

At the boundary between two different materials, they can either be absorbed or transmitted

Why is human hearing limited?

The conversion of sound waves to vibrations of solids works over a limited frequency range

How is sound heard?

Sound waves cause the ear drum and other parts to vibrate which causes the sensation of sound

What is the frequency range of human hearing?

2hx-20kHz

How can the distance away from a boundary be worked out?

The time taken for the reflections to reach a detector

How are ultrasound waves used for medical imaging?

They are partially reflected when they meet a boundary between two different media

-This allows ultrasound waves to be used for both medical and industrial imaging.

What type of waves do earthquakes produce?

Seismic

What are the types of seismic waves?

-P-waves

-S-waves

What are p-waves?

-Longitudinal, seismic waves

-They travel at different speeds through solids and liquids

What are s-waves?

Transverse, seismic waves

-They cannot travel through a liquid

What do seismic waves provide evidence for?

The structure and size of the Earth’s core

How are objects detected in deep water?

Echo sounding using high frequency sound waves

How is water depth measured>

Echo sounding using high frequency sound waves