5.1 Fundamental of waves

MODUL PDP SPM PASCA PKP
NEGERI PERAK 2020

PHYSICS Form 4

5.1: Fundamentals of Waves

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5.1 Fundamentals of Waves

Learning Standard:

Pupils are able to:

• describe waves.
• state the types of waves.
• compare transverse waves and longitudinal waves.
• explain the characteristics of waves:

(i) Amplitude, A
(ii) Period, T
(iii) Frequency, f
(iv) Wavelength, λ
(v) Wave speed, v
• sketch and interpret wave graphs:
(i) displacement-time
(ii) displacement-distance
• determine wavelength, λ, frequency, f dan wave speed, v.

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5.1 notE

5.1 Fundamentals of Waves
1. Definition of waves – a product when a medium vibrates at a fixed position.
(a) Examples of waves formed in daily life.

Striking a leather membrane covered Object falling on the surface of
drum, kompang produces sound water produces water waves

(b) Activity 5.1: To study the production of waves by an oscillating system and a vibrating
system.

(i) Iron bob is hung at the end of a spring, it is pulled down until it touches the water
surface and then released.

The oscillation of iron bob at the same track will
cause the bob to touch the water surface
periodically. As a result, the water molecules will
vibrate and produce water waves on the water
surface.

(ii) A table tennis ball is placed on a vibrating tuning fork.

The vibration of the tuning fork in the air
produces sound waves. Table tennis ball will
vibrate because the energy is transferred from
the tuning fork to the table tennis ball. The
vibration of the table tennis ball and tuning fork
produces sound waves.

Vibrating system or oscillating system is a system that moves repetitively at
an equilibrium position in a closed path.
In conclusion, waves are produced by an oscillating or vibrating system in
a medium.

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2. Waves transfer energy without transferring matter
Activity 5.2 : Slinky spring is moved from side to side horizontally at end A while end B is
fixed. Red ribbon represents the molecules of the medium/slinky spring.

Figure 5.4 Waves transfer energy without transferring matter

Movement of waves from end A to end B transfer energy from A to B.
The ribbon only vibrates about in a fixed position. The ribbon does not move in the
direction in which the energy is transferred by the waves.
Conclusion :
(i) waves are produced when a medium vibrates at a fixed position.
(ii) Propagation of the waves transfers energy from one place to another without

transferring the matter of the medium.
3. Types of waves

(a) Wave profile
(i) Wave profile is the shape of the slinky spring as waves propagate through.
(ii) The wave profile propagates with time along the direction of propagation of the
wave is known as progressive wave.

Diagram shows the shape /wave profile of the slinky
spring at five consecutive instances after end A has
been moved.
This activity shows the wave profile propagates
with time along the direction of propagation of the
wave which produces progressive wave.

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The photograph shows an example of a
progressive wave produced by the
vibrations on the surface of the water in all
directions.

3 (b) Stationary wave

(i) Stationary wave is a wave where the profile of the wave does not propagate with
time.

(ii) Stationary wave is produced when two identical progressive waves moving in
opposite directions collide with one another.

(iii) Stationary waves are also produced by musical instruments such as ukulele, flute
and drum when these instruments are played.

Diagram shows a wave profile at
five consecutive instances.
Wave produced along a guitar
string being plucked is an
example of a stationary wave.

4. Waves can also be classified as mechanical waves and electromagnetic waves.
Table shows the characteristics of a mechanical wave and an electromagnetic wave.

Mechanical wave Electromagnetic wave

• Requires a medium to transfer energy • Does not require a medium to transfer

from one point to another energy

• Made up of vibrating particles of a • Made up of oscillating electric and
medium magnetic fields perpendicular to one
another
• Water waves, sound waves and
seismic waves on the surface of the • Radio waves, light waves and gamma
Earth are examples of mechanical rays are examples of electromagnetic
waves. waves.

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5. Comparison between Transverse Wave and Longitudinal Wave
There are two types of progressive waves, which are transverse wave and longitudinal
wave.

Transverse wave Longitudinal wave

Definition: Definition:
Transverse wave is a wave which Longitudinal wave is a wave which
the particles of the medium vibrate the particles of the medium vibrate
in the direction perpendicular to in the direction parallel to the
the direction of propagation of the direction of propagation of the
wave. wave.

Radio waves, light waves and Sound wave
water waves

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6. Characteristics of Waves Definition
(a) Term Maximum displacement of a particle from its
equilibrium position
Amplitude, A
The time taken by a particle to make one complete
Period, T oscillation or by a source to produce one complete
cycle of wave
Frequency, f
Number of complete oscillations made by a particle or
Wavelength, λ number of cycles of wave produced by a source in one
(Transverse wave) second

Wavelength, λ Distance between two consecutive points in phase/
(Longitudinal wave) Distance between two consecutive crests/ Distance
between two consecutive troughs
Wave speed, v
Distance between two consecutive points in phase/
Distance between two consecutive compressions/
Distance between two consecutive rarefaction

Distance travelled per second by a wave profile

If a wave profile moves in time,

t = period of wave, T

Thus, the distance travelled by the wave

s = wavelength, λ

Wave speed, v = = λ ,


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7. Graph of Wave Motion Information obtained:
(a) Graph Displacement - time
Amplitude, A
(b) Graph Displacement – distance
Period, T

Frequency, f =


Information obtained:
Amplitude, A
Wavelength, λ

8. Problem solving

(a) Graphs show the propagation of progressive wave in a medium. (v) speed, v
Based on the graphs below, determine
(i) amplitude, A (ii) period, T (iii) frequency, f (iv) wavelength, λ
for the waves.

Answer :

(i) A = 3 cm (ii) T = 0.50 s (ii) f = 1/0.5 = 2 Hz (iv) λ = 16 cm

(v) Speed, v = f λ = (2)(16) = 32 cm s−1

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5.1 MIND MAP

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5.1 FAQ

No Questions and Answers
1Q What is a wave?

A A wave is a traveling disturbance that moves through space and matter.
Waves transfer energy from one place to another, but not matter.

2 Q What are the features of a wave?

A Several common wave characteristics include frequency, period,
wavelength, and amplitude.

3 Q What are two types of waves?

A There are two basic types of wave motion for mechanical waves: longitudinal
waves and transverse waves.

4 Q What is Wave and examples?

A Wave is a flow or transfer of energy in the form of oscillation through a
medium – space or mass. Sea waves or tides, a sound which we hear, a
photon of light travelling and even the movement of small plants blown by
the wind are all examples of different types of waves.

5 Q What is the difference of transverse wave and longitudinal wave?

A Transverse waves are always characterized by particle motion being
perpendicular to wave motion. A longitudinal wave is a wave in which
particles of the medium move in a direction parallel to the direction that the
wave moves.

6 Q What is the purpose of waves?

A Waves are a very important and necessary part of the workings of our planet;
the motions they create perform a vital role in transporting energy around
the globe and shaping the coastlines.

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5.1 Exercise

SECTION A

1 Which of this is a correct example of a longitudinal wave and of a transverse
wave?
[MEMAHAMI]

Longitudinal wave Transverse wave

A Gamma ray Light

B Sound Gamma ray

C Light Radio

D Radio Sound

2 Diagram below shows a wave pattern.

[MENGETAHUI]

Displaceme nt D

Sesaran

A

BC

Distance
Jarak

Which of the distances labelled A, B, C or D, represents one wavelength?

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3 Diagram below shows the displacement-time graph of a wave.

5 0.8
Time / s
0 Masa /s
-5
[MENGAPLIKASI KUANTITATIF]
What is the frequency of the wave?

A 0.20 Hz
B 1.25 Hz
C 2.50 Hz
D 5.00 Hz

4 Diagram below shows a displacement-distance graph of a wave. The frequency of
the wave is 5 Hz.

Displacement/ cm 8 Distance/ cm
Sesaran/ cm Jarak/ cm
0.5

04
-0.5

Find the velocity of the wave. .[MENGAPLIKASI KUANTITATIF]

A 4 cm s-1 B 6 cm s-1
C 48 cm s-1 D 96 cm s-1

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5 Diagram below shows a ball floating in a water tank.
direction of wave

ball arah gelombang
bola

water
air
Which of the following is the correct movement of the ball, when the wave passes?

[MEMAHAMI]
AB

CD

6 Which of the following statements is true about progressive waves
[MENGETAHUI]

A All particles are vibrating
B Profile wave is stationary.
C The particles in the node are stationary
D Consists of nodes and antinodes

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SECTION B
1 Diagram below shows the displacement-time graph of a wave.

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0 0.8

-5 Time / s
Masa /s

(a) What is amplitude?

[MENGETAHUI]

……………………………………………………………………………………………. [1 mark]
(b) Based on the graph above, how much [MEMAHAMI]

(i) Amplitude

……………………………………………………………………………………………. [1 mark]
(ii) Period

…………………………………………………………………………………………….
[1 mark ]

(c) Calculate the frequency of wave.
. [MENGAPLIKASI KAUNTITATIF]

[2 marks]
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2. Diagram 2.1 shows a ripple tank used to generates water waves for the purpose of
studying phenomena of wave.

Diagram 2.1 Diagram 2.2

(a) Underline the correct answer in the brackets. [MENGETAHUI]
. [1 mark]

Water wave is a (transverse, longitudinal) wave.

(b) On Diagram 2.2, mark one distance which is equal to a wavelength of the

water waves. Label the using the symbol λ.
[MENGETAHUI]
[1mark].

(c) When the current passing through the electric motor is increased, what
happens to:
[MEMAHAMI]
(i) The frequency of the water wave?

……………………………………………………………………………………………… [1 mark]
(ii) The wavelength of the water wave?

……………………………………………………………………………………………… [1 mark]
(iii) The speed of the water wave?

……………………………………………………………………………………………… [1 mark]

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QR CODE

Title 5.1 Fundamentals of waves QR CODE
link
5.1 Fundamentals https://youtu.be/obTp0Br_MbU
Of Waves

Measuring Waves https://youtu.be/55z1xL_CBb8
using Ripple Tank
Practical Video

Progressive and https://youtu.be/XWVGL2h9jCM
Stationary Waves

Standing Waves https://youtu.be/J_Oto3mUIuk
Physics Lesson

REINFORCEMENT TEST https://drive.google.com/file/d/1t3h6YElNfTL26t
sfeHJPlupXkxaF5a7y/view?usp=sharing

ANSWER https://drive.google.com/file/d/1bL670F7wMZV

REINFORCEMENT TEST w62cC8REf8Fy3TgFmt-3x/view?usp=sharing

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5.1 Answer

SECTION A
1B
2A
3C
4C
5B
6A

SECTION B
1.

(a) Maximum displacement from the equilibrium position
(b) (i) 5 cm (ii) 0.4 s
(c) f = 1/T

= 1/ 0.4
= 2.5 Hz

2 (a) Tranverse
(b)

(c) I) Frecuency increase
(ii) wavelength decrease
(iii) speed remain same

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