13 Wave Behaviour

8/7/2019 13 Wave Behaviour

1/51

WAVE BEHAVIOURTOPIC 13 : GENERAL WAVE PROPERTIES

PreparedbyCgEdnaMariaHjOsman.E-ma

il:[email protected]

1Monday, February 21, 2011
mailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]


2/51

WAVE BEHAVIOURSimple wave behaviour can be observed using a

Ripple Tank

Ripple Tank

Avibratingdipper,shallowglass-bottomedtray,

alightsourcedirectlyoverthetrayanda

whitescreenbelow. PreparedbyCgEdnaMariaHjOsman.E-ma

il:[email protected]



3/51

WAVE BEHAVIOURRipple Tanks can create:

Plane Wavefronts Circular Wavefronts

These wavefronts are used to observe wave behaviours.

PreparedbyCgEdnaMariaHjOsman.E-mail:[email protected]



4/51

WAVE BEHAVIOURAny wave can behave in the following ways:

Reflected Refracted DiffractedPreparedbyCgEdnaMariaHjOsman.E-mail:[email protected]



5/51

REFLECTION OF WAVESWhen a wave hits a solid barrier / obstacle it will be

bounced outwards in the opposite direction.




6/51

REFLECTION OF WAVESFocus : Reflection of plane waves on straight barriers.

Wavefrontshitting at an angle

Wavefronts hittingstraight on




7/51

CONSTRUCTION OF REFLECTED

WAVESDraw the line representing the direction of

wave travel 90 degrees to the wavefronts

and hitting the reflecting surface.

Incident

Wavefronts

Incident Point PreparedbyCgEdnaMariaHjOsman.E-mail:[email protected]



8/51


WAVES

Use the protractor to create a normal line

at the incident point.

Incident Point

Normal




9/51


WAVES

Use the protractor to measure

the angle between the normal

and the incident line.

Angle

Normal

Incident Line C




10/51


WAVES

This angle is known

as the incident angle

or angle of incidence

Angle

Normal

Incident Line C

PreparedbyCgEdnaMariaHjOsman.E-mail:edna.maria.osman@gmai

l.com



11/51


WAVES

AngleNormal

Incident Line

Use the protractor to measure put and mark the same sizeangle at

the incident point but away the from the normal.

Incident Point

C

PreparedbyCg

EdnaMariaHjOsman.E-mail:edna.maria.osman@gmai

l.com



12/51


13/51


WAVES

ReflectedLineNormal

Incident Line

C

Angle

This angle between thenormal and the reflected

line is known as the

reflected angle or angle of

reflection

PreparedbyCg

EdnaMariaHjOsman.E-mail:[email protected]



14/51


WAVES

Use a ruler to measure the distance between one wavefront to the

next immediate wavefront. This is the wavelength.

Wavelength

PreparedbyCg




15/51


WAVES

Mark these wavelengths consecutively on the reflected line starting

from the incident point.

Incident PointPreparedbyCg




16/51


WAVES

Draw straight lines 90degrees to the reflected

line, on the wavelength

marks to construct the

reflected wavefronts.

ReflectedWavefronts

PreparedbyCg




17/51

REFLECTED WAVES

Angle of

Incidence

Angle of

Reflection=

Wavelength remains constant

Speed remains constant

Frequency remains constant

PreparedbyCg




18/51

REFRACTION OF WAVESThe change in the direction of the wave as they move

from one medium to another.

PreparedbyCg




19/51

REFRACTION OF WAVESThe depth of the medium / substance the waves pass

through will also affect the waves.

Water @depth A

Water @depth B

PreparedbyCg




20/51

REFRACTION OF WATER WAVESWavefronts will be affected as follows when moving

from deep area to shallow area.

ShallowDeep

The wavefronts passes through the different depths straight on.

PreparedbyCg

EdnaMariaHjOsman.E-m

ail:[email protected]



21/51



ShallowDeepWavelength

longerin deep area

Wavelength

shorterin shallow area

The wavelengthdecreases as it moves from deep to shallow area.

PreparedbyCg





22/51



ShallowDeepSpeed

fasterin deep area

Speed

slowerin shallow area

The speeddecreases as it moves from deep to shallow area.

PreparedbyCg





23/51



ShallowDeep

The wavefronts passes through the different depths at an angle.

PreparedbyCg





24/51

REFRACTION OF WATER WAVES

Describe the visible changes found here!

ShallowDeep

PreparedbyCg





25/51


Direction of wave travel changes !

Deep

Shallow

Wave path is refracted towards the normal line.

Refracted wave path

Original wave path

PreparedbyCg





26/51


Wavelength also changes !

Incident wavelength is longer than the refracted wavelength

Deep

Shallow

Refracted wavelength

Incident wavelength

PreparedbyCg





27/51



Deep

ShallowWave path is refracted

towards the normal.

Thewavelengthdecreases.

Thespeeddecreases.

PreparedbyCg





28/51


from shallow area to deep area.

DeepShallow

The wavefronts passes through the different depths straight on.

PreparedbyCg





29/51



DeepShallowWavelength

longerin deep area

Wavelength

shorter

in shallow area

The wavelength increases as it moves from shallow to deep area.

PreparedbyCg





30/51



DeepShallow

The wavefronts passes through the different depths at an angle.

PreparedbyCg


ail:edna.maria.osman@gma

il.com



31/51

REFRACTION OF WATER WAVESDirection of wave travel changes !

Deep

Shallow

Wave path is refracted away from the normal line.

Refracted wave path

Original wave path

PreparedbyCgEdnaMariaHjOsman.E-m


il.com



32/51


Deep

Shallow

Incident wavelength is smaller than the refracted wavelength

Refracted wavelength

Incident wavelength

Wavelength also changes !



il.com



33/51



Deep

Shallow

Wave path is refracted

away from the normal.

Thewavelengthincreases.

Thespeedincreases.



il.com



34/51

CONSTRUCTION OF REFRACTED WAVES

Deep

Shallow

Plane wave passing

through straight on.

Scenario A Scenario B

Plane wave passing

through at an angle. PreparedbyCgEdnaMariaHjOsman.E-m


il.com



35/51


36/51


Draw the line representingthe direction of wave travel

90 degrees to the wavefronts

and hitting the surface.

Deep

Shallow

Scenario A



il.com



37/51


38/51


Use a ruler to measure the

distance between one

wavefront to the next

immediate wavefront.

This is the wavelength.

Wavelength

Deep

Shallow

Scenario A



il.com



39/51


Wavelength

Deep

Shallow

Shallow to Deep : TheWavelengthincreases.

Longer

WavelengthCreate longer wavelengths

for wavefronts in deep area

Scenario A



il.com



40/51


Deep

Shallow

Markthese new longer wavelengths consecutively on the line of

travel starting from the incident point.

Incident Point

Scenario A



il.com



41/51


Deep

Shallow

Draw straight lines 90 degrees to the line of travel, on the

wavelength marks to construct the refracted wavefronts.

Scenario A



il.com



42/51


Deep

Shallow

Scenario B

Plane wave passing

through at an angle. PreparedbyCgEdnaMariaHjOsman.E-m


il.com



43/51


44/51


45/51


DeepShallow

Scenario B

Shallow to Deep : Wave path is refracted away from the normal.

Create the refracted wave path

from the point of incident.

IncidentPoint





46/51


DeepShallow

Scenario B

Shallow to Deep : TheWavelengthincreases.

Wavelength

Longer

WavelengthCreate longer wavelengths

for wavefronts in deep area





47/51


DeepShallow

Scenario B

Markthese new longer wavelengths consecutively on the line of

travel starting from the incident point.

IncidentPoint





48/51


DeepShallow

Scenario B

Draw straight lines 90 degrees to the line of travel, on the

wavelength marks to construct the refracted wavefronts.

PreparedbyC

gEdnaMariaHjOsman.E-m



C O O S


49/51



Deep

Shallow

Wave path is refracted

away from the normal.

Thewavelengthincreases.

Thespeedincreases.

PreparedbyC






50/51



Deep

ShallowWave path is refracted

towards the normal.

Thewavelengthdecreases.

Thespeeddecreases.

PreparedbyC





51/51

SUMMARY OF WAVE BEHAVIOUR

Wavelength

Speed

REFLECTION REFRACTION

Wavelength

Speed

Direction

Angle ofIncidence

Angle ofReflection=

INCREASE /

DECREASECONSTANT

TOWARDS / AWAYFROM NORMAL

DEPENDS ON DEPTH OF MEDIUM

PreparedbyC



Documents

13 Wave Behaviour