PHY - 1. Properties of waves

what are waves

A means of transferring energy from place to place without transferring matter

what are the 4 parts of a wave and label them

1 - wavelength

2 - trough

3 - amplitude

4 - peak

wavelength

The distance between 2 consecutive points

unit: m

symbol: λ

amplitude

the maximum distance of a point on a wave from the equilibrium

Units: vary

symbol: A

Period

The time taken for one complete cycle/ wavelength

unit: s

symbol: T

Frequency

The number of complete cycles (waves) that pass a point in 1 second

unit: Hz

symbol: f

relationship between period and frequency of a wave

period = 1/frequency

T = 1/f

what is a wavefront

an imaginary line running along the crest of a wave

(looks like ladders)

what is the wave equation

wavespeed = frequency x wavelength

V = fλ

transverse waves

Waves in which the oscillations are perpendicular to wave propagation

example of transverse waves (min. 3)

• light waves

• water waves

• radiation waves

• microwaves

• S wave

what are longitudinal waves

Waves in which the oscillations are parallel to wave propagation

Examples of longitudinal waves (min 2.)

• P wave

• sound waves

properties of all waves

• reflect

• refract

• transfer energy

• do not transfer matter

property of longitudinal waves

• all need a medium to travel ( can’t travel in a vacuum e.g. space )

Doppler effect

when a source moves towards an observer, the observed wavelength decrease and the frequency increase

what does a smaller wavelength mean

a higher frequency meaning the noise will be of a higher pitch

how is the doppler effect used to find out the speed of a car with speed guns

• the speed gun bounces waves off the vehicle

• the vehicle is moving when the waves are reflected off it

• the speed of the vehicle will change the speed of waves which can then be measured

this can be applied to other speed measuring objects

what waves on the EM spectrum have larger wavelength but smaller frequency

Radiowaves