Contoh Format LKS

SMSains Muzaffar Syah

1

What is A Transverse Wave?

A transverse wave is a wave in which thevibration of particles in the medium is____________ to the direction ofpropagation of the wave.

Example: _______________________

What is Longitudinal Waves?

A longitudinal wave is a wave which thevibration of particles in the medium is______________ the direction of propagationof the wave.The slinky spring moves backwards andforwards to produce a longitudinal wave.The particles of the medium (spring) move___________ to the direction of the wave.The wave that travels along the springconsists of a series of ___________ and____________.

6.1

What iswaves?

Process of transferring _______ from one location to another which isproduced by an ___________ or ____________ motion.

How dowavestransferenergy?

When energy is transferred by a wave from a vibrating source to a distantreceiver, there is no _________ of matter between the two points.

When a stone is dropped into a pond, ________ waves are produced. The direction of propagation of the water waves is from ______ to ____. The cork represents the water particles. The cork does not move together with the wave, instead it moves _____

and _________ about its initial position. Waves transfer energy as they move along the water particles.

However, the waves do not carry the water particles along with them.


2

Activity 1: To observe a longitudinal wave and a transverse wave using a slinky spring.

1. Hold one end of a slinky spring and give a sharp push at the other end of the spring backwardand forward. Observe the movement of the spring.

(a) Sketch the longitudinal wave produce by the slinky spring.

(b) Label the parts of compression and rarefaction of the spring and the wavelength of thewave produced.

(c) Show the direction of the vibration of the coloured thread and the direction of propagationof the wave (movement of the spring.

(d) The coloured thread which represents a particle of the medium vibrate _________ to thepropagation of the wave.

(e) The wave that travels along the spring consists of a series of ____________ and____________

(f) The _____________ is the distance between two successive rarefraction or twosuccessive compression

2. Use the same slinky spring move the other end of the spring side ways. Observe themovement of the spring.(a) Sketch the transverse wave produced by the slinky spring.

(b) Label the wavelength of the wave produced.(c) Show the direction of the vibration of the coloured thread and the direction of propagation

of the wave (movement of the spring.


3

(d) The vibration of the coloured thread is ____________ to the direction of the propagation ofthe wave.

ConclusionA longitudinal wave is a wave in which the vibration of the medium is _______________to thedirection of the propagation of wave.A transverse wave is produced when the vibration of the medium is ________________ to thedirection of the propagation of wave.

What is a ripple tank?

The phenomenon of water waves can be investigatedusing a ripple tank.The water waves are produced by a __________ bar onthe water surface.

The tank is leveled so that the ________ of water in thetank is uniform to ensure water waves propagate with___________ speed.

How the dark and bright bands are formed on thescreen?

The water acts as a _______ to produce a pattern of________ and _________ regions on a piece of whitepaper placed under the tank when light passes throughit.

Water waves have crests and troughs.

A crest is the highest position of the wave acts as a________ lens, whereas a trough is the lowest positionacts as a __________ lens.

Light rays from the lamp on top will focus onto the whitescreen below. The _________ lines correspond to thecrests, and the _______ lines correspond to the troughs.


4

What is meant by a wavefront?

Lines joining all the points of the ______ phase arecalled wavefronts.

The wavefronts of a transverse wave and longitudinalwave are _____________to the direction of propagationof the waves.

Two types of wavefronts:

1. __________wavefronts 2. ____________ wavefronts

Describing Waves

Vibration/Oscillation : The movement from one extreme position to the other and back to the sameposition.

__________________: The maximum displacement from its equilibrium position. SI unit: meter, m

__________________: The time taken for an oscillation to complete one cycle. SI unit is second (s)

__________________: The number of waves produced in one second. SI unit is Hertz (Hz)

__________________: The distance between two successive crests or two successive troughs or

the distance between two successive compressions or two successive

rarefactions in a sound wave.

__________________:The measurement of how fast a crest is moving from a fixed point.

SI unit is ms-1

.


5

Displacement-time graph and Displacement-distance graph for a wave.The motion of an oscillating spring can be plotted on a displacement against time graph.

O is called the _____________ position. a is the __________. T is the ___________ of theoscillation.

Displacement against distance graph

Displacement of a particle against distance measured along the wave

a = ___________. λ = ____________

Relationship between frequency and wavelength

At constant speed, when the frequency increases, the wavelength will__________. Frequency is ____________ proportional to wavelength.

The relationship between speed, wavelength and frequency


6

Speed = distancetime

For one complete oscillation, the distance traveled is the wavelength of the wave. The time takento travel such distance is period. So,

Speed = wavelengthPeriod

Since period = 1 __ .Frequency , therefore speed = ________ x _________

Exersise 1

1. (a) The wavelength of the wave in the diagram above is given by letter ________

(b) The amplitude of the wave in the diagram above is given by letter ________

2. Indicate the interval which represents one full wavelength.

Answer: ___________

2. What is the frequency of water waves with the wavelength of 4.0 cm and traveling at a speedof 1.6 cm s

-1?

3. Measure the wavelength and calculate the speed of the wave. The frequency of the wave is 50Hz.


7

4. If the speed of light is 3.0 x 108

m s-1

, what is the frequency of light with the wavelength of 8.0x 10

-7m?

5. From the graph, calculate:

(a) Amplitude

(b) Period

(c) frequency

6. A graph shows a wave produce by aslinky spring vibrating at frequency 8Hz. What is:

(a) amplitude

(b) wavelength

(c) wave speed

7. Which of the graphs has a higher frequency?

A BDamping in an Oscillating System


8

What isdamping?

Damping is the decrease in the _________ of an oscillating system when itsenergy is lost as _______ energy.The amplitude of an oscillating system will gradually decrease and become zerowhen the oscillation stops.

What causesdamping?

1. External damping of the system is the loss of energy to overcome ________forces or air resistance.

2. Internal damping is the loss of energy due to the compression and extensionof the molecules in the system.

Sketch agraph toshowdamping

Resonance in an oscillating system

__________Force

Forceoscillation

__________frequency

Resonance

To enable an oscillating system to go on conticously, an external force mustbe applied to the system.

The external force supplies __________ to the system. Such a motion iscalled a forced oscillation

The frequency of a system which oscillates freely without the action of anexternal force is called the natural frequency.

Resonance occurs when a system is made to oscillate at a __________equivalent to its natural frequency by an external force. The resonatingsystem oscillates at its maximum ___________.

Experiment inBarton’spendulum

How doesresonance

The frequency of a simple pendulum depends on the __________ of thependulum.

In Barton’s pendulum experiment, there are many pendulums tied to the rope.Two of the pendulum are of the same length


9

occur in thetwopendulum ofequal length?

When pendulum B oscillates, all the other pendulums are forced to oscillate.

But pendulum D oscillates with the largest __________, ie, pendulum Dresonates

Pendulum B and pendulum D are of the _______ length.

Frequency B ______ Frequency D

Therefore, pendulum B causes pendulum D to oscillate at its naturalfrequency.

Good effectsof resonance

1. The tuner in a radio or television enables us to select the programmes we areinterested. The circuit in the tuner is adjusted until resonance is achieved, atthe frequency transmitted by a particular station selected. Hence a strongelectrical signal is produced.

2. The loudness of music produced by musical instruments such as the trumpetand flute is the result of resonance in the air.

Bad effects ofresonance

3. A bridge can collapse when the amplitude of its vibration increases as a resultof resonance.

Do Experiment 1.2 Practical Book page 4 to study the damping effect in a vibrating systemDo Experiment 1.3 Practical Book page 6 to study resonance Barton’s Pendulum

How does a guitar work?

When the guitar string is plucked, thestring will start to _________ andproduce distinct sounds.The guitar string is attached to the soundbox of the guitar.The vibrating string forces ______particles inside the box to vibrate at thesame natural ___________ as the string.The sound box _________ with the string and sets more air particles to vibrate thus producingloud sound.

TUTORIAL 6.1

1. A simple pendulum is oscillating through 3different positions, A, B and C.

One complete oscillation is fromA. A to BB. A to CC. A to C and C to BD. A to C and C to A

2. The diagram shows the displacement-distance graph for a wave at a giveninstant. The amplitude of the water wavesvaries with distance from their startingpoint.

Which symbols represent the amplitudeand the wavelength?

3. Diagram 1 below shows the cross sectionof water waves.


10

Which of the following statements is trueabout the water waves? (2006)A. T and U have the same phaseB. Wave energy is transferred from

position S to UC. The wave length is the distance

between S and UD. The particle at U oscillates in a

direction parallel to the direction of thewave propagation

4. Diagram 5 shows two situations where aball floats and moves on the surface of thewater.

The direction of the movement of the ballis ….. (2006)A. parallel to the direction of the wave

propagationB. perpendicular to the direction of the

wave propagationC. the same as the direction of the wave

propagationD. the opposite to the direction of the

wave propagation.

5. The diagram shows a waves traveling inthe sea.

Which two points are one wavelengthapart?A. P and RB. Q and S

C. P and SD. Q and T

6. Diagram below shows a load beingoscillated on a spring.

Based on the diagram, which of thefollowing displacement-time graphsrepresents oscillation of the load from P toQ and back to O? (2007)

7. Calculate the frequency of the given wavebelow

A. 8 Hz. D. 1/8 HzB. 4 Hz. E. ¼ HzC. 12 Hz


11

8. Based on the given diagram abovecalculate the wavelength.

A. 4 cmB. 8 cmC. 10 cmD. 15 cmE. 20 cm

9. The diagram shows a wavefront patternproduces by a dipper vibrating at afrequency of 12 Hz in a ripple tank.

What is the speed of the waves? (2005)A. 2 cms

-1

B. 8 cms-1

C. 12 cms-1

D. 18 cms-1

E. 36 cms-1

10. Diagram below shows a wave pattern onwater.

Wavelength is the distance between thepoints …… (2007)

A. P and QB. P and RC. Q and SD. R and S

11. Which of the following shows therelationship between period and frequencyof a wave.

12. Based on the graph given above, what isthe amplitude of the wave?.

A. 5 mB. 10 mC. 15 mD. 20 mE. 25 m

13. The diagram shows the displacement-timegraph of an oscillating system.

The system which produces this graph ishaving a

A. perpertual oscillationB. forced oscillationC. damped oscillationD. resonance


12

14. Which of the following quantity decreaseswhen a system under goes damping?

A. amplitude.B. Velocity.C. Wave length.D. Frequency

15. The graphs show the cross-sections ofwater waves. Which wave has the greatestenergy? (2005)

16. A system has a natural frequency ofoscillation equals to f. An external force issupplying energy to the system toperpetuate the oscillations of the system.Resonance will occur in this system ifenergy is supplied to the system if energyis supplied to the system at a frequencyequal to(A) f

(B) f2

(C)2

f

(D)2

f

16. Which graph represents a wave withamplitude of 4.0 cm and period of 0.05 s?(2004)

17. A dipper produces plane waves at therate of x waves per second in a rippletank. The wavelength of the plane waveis λ cm. What is the wavelength of the plane wave if the dipper produces 2xwaves per second?

A. B. 2

C. 2

1D.

4

1


13

18. A boy on a swing which has a period of 2s. It is allowed to swing until it stops.

Which of the following graphs shows theoscillation of the swing?

Structure Questions1. The diagram shows a displacement –

distance graph of a transverse wavemotion.

(a) On the graph, label:(i) direction of the vibration of the

particles medium(ii) direction of the propagation of the

wave.

(b) Give one example of transverse wave.

(c) Find(i) Amplitude

(ii) Wavelength

(d) If the frequency is 25 Hz, find the wavespeed.

2. The diagram shows a tuning fork whichproduced a longitudinal wave.

(a) Why does sound wave is alongitudinal wave?

(b) Mark on the diagram(i) with a letter C which represents a

point of compression.(ii) With a letter R which represents a

point of rarefaction.(iii) With a letter λ which represents the

wavelength

(c) From the graph, find(i) Amplitude

(ii) wavelength

(d) If the speed of the sound wave is 330ms

-1, find its frequency.


14

3. Diagram shows a simple pendulum whichconsists of a bob of mass 40.0 g at theend of a light inelastic string of length20.0 cm. The pendulum makes 20complete oscillations in 5.0 s.

(a) By using the letters A,B and C in thediagram above state the

(i) equilibrium position

(ii) the meaning of period

(b) What is the frequency of theoscillations of the pendulum ?

(d) What happens to the frequency ofthe oscillations of the pendulumwhen the length of the pendulum is80.0 cm ?

(e) After a while the pendulum stops tooscillate .

(i) Explain why?

(f) Plot a graph displacement – time toshow why the pendulum stops tooscillate.

(g) State the form of energy when thependulum

(i) at B (ii) at C

Documents

Contoh Format LKS