2What is a Wave?"A wave can be described as a disturbance that travels through a medium from one location to another location ."
3Transverse Wave Motion A group of people jumps up and sits back down, some nearby people see them and they jump up, some people further away follow suit and pretty soon you have a wave travelling around the stadium. The wave is the disturbance (people jumping up and sitting back down), and it travels around the stadium. However, none of the individual people the stadium are carried around with the wave as it travels - they all remain at their seats
4Transverse waveIn a transverse wave the particle displacement is perpendicular to the direction of wave propagationThe particles do not move along with the wave; they simply oscillate up and down about their individual equilibrium positions as the wave passes by .Light waves are transverse in nature.
5Transverse wave Transverse waves on a string The string is displaced up and down as the wave travels from left to right, but the string itself does not experience any net motion.
6RIGHT ANGLES TO WAVE DIRECTION TRANSVERSE WAVEvibrationsWAVE DIRECTIONVIBRATIONS ARE AT 90O ORRIGHT ANGLES TO WAVE DIRECTION
7longitudinal waveIn a longitudinal wave the particle displacement is parallel to the direction of wave propagation The particles do not move down the tube with the wave; they simply oscillate back and forth about their individual equilibrium positions. Pick a single particle and watch its motionSound waves are longitudinal
8VIBRATIONS ARE PARALLEL LONGITUDINAL WAVEvibrationsWAVE DIRECTIONVIBRATIONS ARE PARALLELTO WAVE DIRECTION
9Parts of a waveThe crest of a wave is the point on the medium which exhibits the maximum amount of positive or upwards displacement from the rest positionThe trough of a wave is the point on the medium which exhibits the maximum amount of negative or downwards displacement from the rest position.
10AmplitudeThe amplitude of a wave refers to the maximum amount of displacement of a particle on the medium from its rest position.
11WavelengthThe wavelength of a wave is the distance between any two adjacent corresponding locations on the wave train.This distance is usually measured in one of three ways:crest to next crest,trough to next trough,or from the start of a wave cycle to the next starting point.
12All waves are caused by vibrations Diagram of a waveAll waves are caused by vibrationsPEAK OR CRESTWAVELENGTHAMPLITUDETROUGHWAVELENGTH
13Frequency and Time period The frequency (f) of a wave is the number of cycles that pass the observer in a given time.Hertz is the unit of frequency.Frequency and period are exact inverses of each other, f = 1 / T or T = 1 / f
14Finding the relationship between WAVESPEED, FREQUENCY & WAVELENGTH 10mFrequency =4HzWhat is the relationship?Wavelength =5 mWavespeed =20 m/s
15WS F x WL WS = F x WL F = WS WL WL = WS F wave speed (m/s) = frequency (Hz) x wavelength (m)WS = F x WLF = WSWLWL = WSFWSFxWL
16Wave EquationThe relation between the speed (v) of a wave ,its wavelength (λ) and frequency (f) is given bySpeed = Wavelength x FrequencyUsing the symbols v, λ , and f, the equation can be rewritten asv = f x λ
171. If the speed of a wave is 340m/s, and its wavelength is 20m, what is its frequency? wave speed = frequency x wavelength340 = frequency x 20frequency = = 17 Hz20
18If 300 cycles are produced in 60s and the wavelength is 10m, find:- (a) the frequency300 cycles60s(b) the wave speedwave speed = frequency x wavelength= 5 cycles/s= 5 Hz= 5 x 10= 50 m/s
19Light waves travel at 300 000 000 m/s Light waves travel at m/s. If their frequency is 500Hz, find their wavelengthwave speed = frequency x wavelength= x wavelength=500m
20If 25 cycles occur in 1 second and their wavelength is 3 metres, find the wave speed wave speed = frequency x wavelength= x 3= m/s
21WAVEFRONTS PEAK/CREST WAVELENGTH WAVEFRONTS (PEAK/CREST OF WAVES FROM ABOVE)
22Each line is a peak/crest of a circular wave Circular WavefrontsEach line is a peak/crest of a circular wave