Physics C.2 Wave model

Pulses

A single oscillation or disturbance in. amedium

Fixed end - flips

Free end - reflects back

Superposition

When two pulses meet the resulting pulse is the sum of them, so their amplitudes add.

Transverse Wave

Wave in which the vibrations of the particles are at right angles (perpendicular) to the direction of travel.

Continuous progressive (traveling) wave

Series of periodic pulses, involves a transfer of energy and each point on the wave has the same amplitude.

Longitudinal wave

The vibrations of the particles are along the same direction (parallel) to direction of wave travel

Example of transverse waves

• radio waves

• light waves

• seismic S waves

• water waves

Example of longitudinal waves

• sound waves

• shock waves

• seismic P waves

Sound waves

• they require particles to move in order to transfer the energy

• waves can reflect (echo)

• when sound passes from warm air into cold air it refracts

properties of all colors

• frequency

• amplitude

• wave length

• move at the speed of light

• do not require a medium to travel through

• transverse waves

• all transfer energy

• can be reflected or refracted

Intensity

A measure of the brightness of light measured in W m^-2. It is proportional to the square of the wave amplitude.

Difference between mechanical and EM waves

EM waves don’t require a medium, mechanical waves do