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6.1WAVES

DESCRIBINGWAVES

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LEARNING OUTCOMES State what is meant by a wavefront

State the direction of propagation of

waves in relation to wavefronts

Define period

Define frequency

Define wavelength

Define wave speed

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Ripple Tank The phenomenon ofwater waves can be

investigated using aripple tank.

The water waves are

produced by a

__________ bar on the

water surface.

vibrator

The tank is leveled so

that the ________ of

water in the tank is

uniform to ensure waterwaves propagate with

___________ speed.

depth

constant

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Ripple tank

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When the motor

is switched on,plane waves areproduced.

A round dipper

fixed to the barwill producedcircular waves.

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How the dark and bright bands areformed on the screen?

The water acts as a_______ toproduce a patternof ________ and

lens

bright

_________on a piece of whitepaper placedunder the tank

when light passesthrough it.

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Water waves have crests and

troughs.

A crest is the highestposition of the wave acts as a

________ lens and will focus

the light rays. So _______

re ion will roduced.

convex

bright

A trough is the lowest

position acts as a __________

lens and will diverge the

light rays. So _________region will be produced.

concave

dark

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Wavefronts

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What is meant by a wavefront? Lines joining all the points of the ______

phase are called wavefront.

same

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2 Types of wavefrontPlane waves Circular Waves

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The direction of propagation of wavesin relation to wavefronts The wavefronts of a transverse wave

and longitudinal wave are_____________to the direction ofperpendicular

propagation of the waves.

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Describing Wavesmp u e

Period

Frequency

WavelengthWave speed

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Amplitude The maximum displacement from its

equilibrium position.

SI unit: meter, m

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Amplitude A mass, m, is hung to a spring. The

spring is at rest or in the equilibriumposition at O

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The amplitude, a, is the distance fromthe equilibrium position, O to themaximum displacement X or Y

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The amplitude, a, is the distance fromthe equilibrium position, O to themaximum displacement X or Y.

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Period, T When the

pendulumswings from A to

B and back to A,the pendulum issaid to havedone one

completeoscillation

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Period, T The time taken

for an oscillationto complete one

The number ofwaves producedin one second.

Frequency, f

cycle.

SI unit is second(s)

SI unit is Hertz(Hz)

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Frequency & period

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Frequency & period

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What is the frequency of the swinging

plasticine ball?

Period is the time required to complete

one oscillation

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Wavelength,

Wavelength, , is the distance between twoconsecutive points which are in phaseSI unit: meter, m

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Wavelength,

For a transverse wave,Wavelength, , is the distance between twosuccessive crest or trough.

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Wavelength,

For a longitudinal wave, the wavelength, , isthe distance between two successivecompressions or rarefractions.

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Speed, v The measurement of how fast a crest ismoving from a fixed point.SI unit is ms-1.

Wave Speed, v

SI unit is ms-1.

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QUESTION 2

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QUESTION 3

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QUESTION 4