Edexcel ScienceiGCSE Physics

B.Fundamentals of Waves2019-2020

Name:________________Physics Teacher:______________

House CG Test Score

Year 9

Specification Checklist

3.01 use the following units: degree (°), hertz (Hz), metre (m), metre/second (m/s) and second (s)

3.02 explain the difference between longitudinal and transverse waves 

3.03 know the definitions of amplitude, wavefront, frequency, wavelength and period of a wave

3.04 know that waves transfer energy and information without transferring matter

3.05 know and use the relationship between the speed, frequency and wavelength of a wave:

wave speed = frequency × wavelength

v = f × λ

3.06 use the relationship between frequency and time period:

time period = 1 ÷ frequency

T=1f

3.07 use the above relationships in different contexts including sound waves and electromagnetic waves

Fundamentals of Waves – Science (Physics) 2

Key Words

Key Word Image Definition

Amplitude The height of the wave from midpoint to peak.

Electromagnetic Spectrum

A group of transverse waves that all travel at the speed of light. They have both an electric and magnetic part.

Frequency The amount of complete waves passing a point every second.

Hertz The unit for frequency. [Hz]

Longitudinal A wave that oscillates parallel to the direction of energy transfer.

Medium The substance a wave travels through.

Oscillation A vibration.

Parallel In the same direction as.

Perpendicular At 90 degrees to.

Time Period The time taken for one complete wave to pass.

Transverse A wave that oscillates perpendicular to the direction of energy transfer.

Vacuum A space with no particles at all.

Wavefront The approaching crest of the wave e.g. Carl sees two wave fronts pass by him as he is watching waves on the beach.

Wavelength The distance from peak to peak.

Fundamentals of Waves – Science (Physics) 3

1: Transverse and Longitudinal Waves

Forces Recap Quiz

Use the knowledge you have gained in previous lessons to answer the following questions:

1. What is the mass of an object that weighs 562N?

……………………………………………………………… (2)

2. State Hooke’s Law

…………………………………………………………………………………………………………………………………………………………………………………… (1)

3. What is a scalar quantity?

…………………………………………………………………………………………

………………………………………………………………………………………… (1)

4. A cyclist is accelerating down a hill. What can you say about the forces on the bike?

…………………………………………………………………………………………

………………………………………………………………………………………… (2)

5. What is the ‘centre of gravity’?

…………………………………………………………………………………………

………………………………………………………………………………………… (1)

6. Draw a force-extension graph with a loading and unloading curve for an object that

behaves elastically.

(3)

Score [ /10]

Fundamentals of Waves – Science (Physics) 4

Learning Outcomes:

1. Identify the two different types of wave and know that they transfer energy and information.

2. Give the definition of transverse and longitudinal waves. 3. Sketch and label a diagram representing transverse and longitudinal waves.

The two different types of waves.

Key Ideas

1. The two different type of waves are transverse and longitudinal. 2. Transverse waves: The oscillation of the wave is perpendicular (at a right angle) to

the direction of energy transfer. 3. Longitudinal waves: The oscillation of the wave is parallel to the direction of energy

transfer. 4. All waves transfer energy and information. 5. It is important to know how to label and define the amplitude and the wavelength. 6. Wavefronts are created by overlapping lots of different waves. It is a line where all

the vibrations happen at the same time and are the same distance from the source (e.g. a water wave)

Fundamentals of Waves – Science (Physics) 5

B1: Demonstrating Waves

In this investigation you are going to use a slinky todemonstrate the two different types of waves.

The method is written in the questions and will be underlined so it is vital that you work methodically through these.

B1: Method and questions

1. Can you create a transverse wave with the slinky?

How did you do this?

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

2. Try to increase the wavelength of your transverse wave.

How did you do this?

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

3. Try to decrease the amplitude of your transverse wave.

How did you do this?

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

4. Can you create a longitudinal wave with the slinky?

How did you do this?

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

5. Try to decrease the wavelength of your longitudinal wave.

How did you do this?

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

Fundamentals of Waves – Science (Physics) 6

Health and Safety Check!

Slinkys are fragile – I willbe sensible with them to avoid tangles.

6. Try to increase the amplitude of your longitudinal wave.

How did you do this?

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

7. Create a transverse wave then a longitudinal wave

What happens when the wave reaches your partner’s hand?

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

8. Create a longitudinal wave on both ends of the slinky at the same time

Describe what happened.

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

9. Create a transverse wave on both ends of the slinky at the same time

Describe what happened.

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

10. What do you think will happen if you create a transverse wave at one end of the slinky

and a longitudinal wave on the other end?

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

11. Test your above hypothesis.

What were your results?

……………………………………………………………………………………………………….

……………………………………………………………………………………………………….

Fundamentals of Waves – Science (Physics) 7

Worksheet – Types of Waves

Use what you have learnt in today’s lesson to answer the following questions.

1. Label the amplitude and wavelength (twice – in two different places) on the transverse wave below [4]:

2. Label the wavelength on each of the longitudinal waves below [2]:

3. Sketch the requested waves in the boxes below [8]:

A transverse wave with a large amplitude

A transverse wave with a short wavelength

A longitudinal wave with a large wavelength

A transverse wave with a small amplitude and short

wavelength

A longitudinal wave with a short wavelength

A transverse wave with a medium amplitude and long

wavelength

4. State the similarities and differences between longitudinal and transverse waves. [3]

…………………………………………………………………………………………………

…………………………………………………………………………………………………

…………………………………………………………………………………………………

Score [ /17]

Fundamentals of Waves – Science (Physics) 8

2: The Wave-Speed Equation

Sketching Waves

1. Sketch a Transverse wave below and label on the wavelength and the amplitude.

2. Sketch a Longitudinal wave below and label on the wavelength.

3. Challenge: Can you sketch below:a. A transverse wave with a smaller amplitude than Q1b. A longitudinal wave with a shorter wavelength than Q2

Fundamentals of Waves – Science (Physics) 9

Learning Outcomes:

1. Define the terms in the equation:v=f × λ

2. Rearrange and use the equation:v=f × λ

3. Identify the different prefixes you may come across in questions (e.g mega, kilo, nano, micro).

The Wave-Speed Equation

Prefix Value

Mega [M]

Kilo [k]

Centi [c]

Milli [m]

Micro [μ]

Nano [n]

Key Ideas

1. Wavespeed, frequency and wavelength are linked in the equation:

wavespeed=frequecy ×wavelength2. In the equation above we measure wavespeed in meters per second [m/s],

frequency in Hertz [Hz] and wavelength in meters [m]3. Frequency is a defined as the number of complete waves per second. 4. Some key prefixes you will need for this topic are ‘mega’ [M = x106], ‘kilo’ [k = x103],

‘milli’ [m = x10-3], ‘micro’ [µ = x10-6] and ‘nano’ [n = x10-9],

Worked Examples

Fundamentals of Waves – Science (Physics) 10

1. What is the speed of a wave with a frequency of 250Hz and a wavelength of 0.5m?

2. What is the frequency of a sound wave (wavespeed = 340m/s) which has a wavelength of 8mm?

3. Happy-FM broadcasts at a frequency of 104.9MHz. Radio waves travel at the speed of light (3 x 108 m/s = 300 000 000m/s). What is the wavelength of these waves?

Fundamentals of Waves – Science (Physics) 11

Worksheet – The Wave-Speed Equation

Complete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. What is the wavespeed of a sound wave which has a frequency of 560 Hz are a wavelength of 0.6m?

…………………..

2. A wave has a frequency of 675Hz and a wavelength of 3m. What is its’ wavespeed?

…………………..

3. A wave with a wavelength of 25cm has a frequency of 2500Hz. What is the wavespeed of the wave?

…………………..

4. Sound waves travel at 340 m/s. What is the frequency of a sound wave that has a wavelength of 0.11m?

…………………..

5. The speed of a wave is 65 m/s. If the wavelength of the wave is 0.8 metres, what is the frequency of the wave?

…………………..

6. A wave with a frequency of 500 Hz is traveling at a speed of 200 m/s. What is the wavelength?

…………………..

7. FM or short-wave local radio is transmitted at 95 200 000 Hz. What is the radio wavelength? Radio waves travel at the speed of light = 300 000 000 (3 x 108) m/s

…………………..

Fundamentals of Waves – Science (Physics) 12

Harder Questions

8. Some earthquake waves have the low frequency of 0.2 Hz and a speed of 8 km/s. What is their wavelength?

…………………..

9. A sound wave travels at 340m/s. What would the frequency be if the wavelength of the wave was 90nm?

…………………..

10. A light wave has a frequency of 250MHz. What is its’ wavelength? Speed of light = 300 000 000 (3 x 108) m/s

…………………..

11. If a wave has a frequency of 360kHz and a wavelength of 60mm, what would it’s wavespeed be?

…………………..

12. How fast is a wave travelling if it has a wavelength of 650µm and a frequency of 35Hz?

…………………..13. What is the frequency of a sound wave with a wavelength of 2km?

…………………..

14. How many waves pass per second if a wave with a wavelength of 2cm is travelling at 6km/s?

…………………..

Fundamentals of Waves – Science (Physics) 13

3: Time Period

Review: Using the wave-speed equationUse your knowledge from the previous lesson to answer the questions below:

1. What is the wavespeed of a wave with a frequency of 375 Hz and a wavelength of 8.2m?

……………………….[3]

2. What is the frequency of a sound wave with a wavelength of 7cm? Sound travels at 340m/s in air.

……………………….[3]

3. What is the wavelength of a radio wave that emits a frequency of 654MHz? Radio waves travel at the speed of light = 3 x 108 m/s.

……………………….[3]

4. How fast would a wave with a frequency of 65kHz and a wavelength of 25nm be travelling?

……………………….[3]

5. On the longitudinal wave below, label the wavelength in two different places.

[2]

[Score /14]

Fundamentals of Waves – Science (Physics) 14

Learning Outcomes:

1. Define the time period and frequency of a wave.2. Rearrange and use the equation:

f= 1T

3. Understand how to read an oscilloscope trace.

Time Period and Frequency

Key Ideas

1. Frequency and time period are linked in the equation

Frequency= 1Time Period

2. In the equation above we measure frequency in Hertz [Hz] and time period in seconds [s]

3. Frequency is a defined as the number of complete waves per second. 4. Time period is a defined as the time taken for one complete wave to pass. 5. This equation is often used in conjunction with the wave-speed equation.

Fundamentals of Waves – Science (Physics) 15

Worked Examples

1. What is frequency of a wave with a time period of 6s?

2. Louise is watching waves pass her in the see. She counts 8 waves passing her in 1 minutes. What is the time period of the waves?

3. A wave has a time period of 15s and a wavelength of 0.4m. How fast is the wave travelling?

Fundamentals of Waves – Science (Physics) 16

Worksheet – Time Period Calculations

Complete the questions below using the equation you have just learnt. You must show all of your working [equation, substitution, solution and units]

1. What is the period of a pendulum that has a frequency of 0.5 Hz?

…………………..

2. The frequency of a vibrating object is 15 Hz. What is the time period of this vibration?

…………………..

3. What is the frequency of long wave radio signal that has a period of 1 millisecond?

…………………..

4. An ocean wave has been observed with a period of 16 seconds. What is the frequency of this wave?

…………………..

5. A beam of red light has a time period of 2ms. What is the wavelength of this red light? Speed of light = 300 000 000 (3 x 108) m/s

…………………..

6. Physics-FM broadcasts a signal with a time period of 230ns. What is the wavelength of these radiowaves? [Hint: Have you done a questions about radiowaves before?]

…………………..

7. A water wave is travelling at a speed of 25m/s. If it takes 1.5 seconds for one wave to pass, what is the distance between the crests of the waves?

…………………..

Fundamentals of Waves – Science (Physics) 17

B2: Measuring Frequency with an Oscilloscope

In this investigation you are going to use an oscilloscope to measure the frequency of a signal.

An oscilloscope displays time on the x-axis.

On the wave below mark one the distance of 1 time period:

This oscilloscope has a time base of 2ms. This means that one square across the x-axis equals 2ms. Using this information can you work out the time period of the wave?

Time Period = …………………… s

Use this time period to calculate the frequency of the wave:

Frequency = ……………………

Method

1. Connect the signal generator to the oscilloscope. 2. Alter the time-base on your oscilloscope until you can clearly see the waveform.3. Note down the time base you are using!4. Measure the time period of your

wave.5. Calculate the frequency of your

wave. 6. Repeat for a number of different

input frequencies.

Fundamentals of Waves – Science (Physics) 18

Health and Safety Check!

I will handle electrical components with care and report any equipmentthat seems damaged

Results

Signal 1

Time Base Used

Time Period [s]

Frequency [Hz]

Signal 2

Time Base Used

Time Period [s]

Frequency [Hz]

Signal 3

Time Base Used

Time Period [s]

Frequency [Hz]

Signal 4

Time Base Used

Time Period [s]

Frequency [Hz]

4: Measuring Frequency

Fundamentals of Waves – Science (Physics) 19

Knowledge and Understanding QuizUse the knowledge you have gained in the previous few lessons to answer the following questions:

1. What is the definition of a longitudinal wave?

……………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………… (2)

2. What is the definition of frequency?

………………………………………………………………………………………… (1)

3. A wave is travelling at 460m/s and has a frequency of 5kHz. What is the wavelength

of the wave?

(3)

4. The oscilloscope display below has a time base of 5ms. What is the:

a. Time period

b. Frequency

(4)

Score [ /10]

Learning Outcomes:

Fundamentals of Waves – Science (Physics) 20

1. Describe the relationship between frequency and pitch of a sound wave2. Describe the relationship between volume (loudness) and amplitude for a sound

wave3. Use an oscilloscope to measure the frequency of a sound wave

B3: Measuring Frequency with a Microphone

In this investigation you are going to connect amicrophone to an oscilloscope and use this to measurethe frequency of a sound.

Method

1. Connect the microphone to the oscilloscope 2. Connect the signal generator to a loudspeaker3. Set the loudspeaker to emit a constant frequency.4. You must keep your microphone pointing towards your loudspeaker. 5. Note down the time base you are using!6. Measure the time period of your sound wave.7. Calculate the frequency of your wave. 8. Repeat for a number of different pitches of sound.

Fundamentals of Waves – Science (Physics) 21

Health and Safety Check!

I will handle electrical components with care and report any equipmentthat seems damaged

Results

Sound 1

Time Base Used

Describe the pitch of the sound you are hearing:

Time Period [s]

Frequency [Hz]

Sound 2

Time Base Used

Describe the pitch of the sound you are hearing:

Time Period [s]

Frequency [Hz]

Sound 3

Time Base Used

Describe the pitch of the sound you are hearing:

Time Period [s]

Frequency [Hz]

Sound 4

Time Base Used

Describe the pitch of the sound you are hearing:

Time Period [s]

Frequency [Hz]

Fundamentals of Waves – Science (Physics) 22

Conclusions from your investigation.

1. How did the pitch of the sound relate to the frequency? [2]

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

2. For the louder sounds, what change did you see on the Oscilloscope? [1]

……………………………………………………………………………………………

……………………………………………………………………………………………

3. What variable did you have to keep the same in this investigation? [1]

……………………………………………………………………………………………

……………………………………………………………………………………………

4. What were the limitations or difficulties in the investigation? [2]

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

5. Can you come up with a way to improve the investigation? [1]

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

6. What would you expect to happen to the display on your oscilloscope if you moved

the microphone further away from the speaker? [2]

……………………………………………………………………………………………

……………………………………………………………………………………………

……………………………………………………………………………………………

Fundamentals of Waves – Science (Physics) 23

Worksheet: Oscilloscope Traces

1. For the oscilloscope traces below, work out the time period and the frequency. [8]

Time base = 0.02s Time base = 3ms Time base = 1ms Time base = 6μs

T T T T

f f f f

2. On the oscilloscope screens below, add the traces you would expect to see for the sound described. [6]

Score [ /14]

Fundamentals of Waves – Science (Physics) 24

Stretch Activity – Wave Interference

During investigation B1 you created waves at two ends of a slinky. You may have noticed some strange behaviour when the waves collided. What the YouTube video linked below and use the box to make some rough notes as you watch.

https://www.youtube.com/watch?v=x2Iwrhynq9o

Summarise what you have learnt in the space below:

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

Fundamentals of Waves – Science (Physics) 25

Fundamentals of Waves

Past Paper Questions

Q1.

The diagram shows a water wave.

Fundamentals of Waves – Science (Physics) 26

(a) (i) The amplitude of the wave is(1)

   A    1 cm

   B    2 cm

   C    4 cm

   D    8 cm

(ii) The wavelength of the wave is(1)

   A    2 cm

   B    4 cm

   C    8 cm

   D    20 cm

(b) Describe one difference between transverse and longitudinal waves.Draw a labelled diagram to help your answer.

(3)

      .............................................................................................................................................      .............................................................................................................................................      .............................................................................................................................................      .............................................................................................................................................

  (Total for question = 5 marks)

Fundamentals of Waves – Science (Physics) 27

Q2.

The diagram shows a wave on the sea.

(a) (i) Which letter shows the wavelength of the wave?(1)

   A   

   B   

   C   

   D   

(ii) Which letter shows the amplitude of the wave?(1)

   A   

   B   

   C   

   D   

(b) A man watches some waves pass his boat.He sees the crest of the waves pass him every 5 s.Calculate the frequency of these waves.

(2)

Frequency = ........................................................... Hz

(Total for question = 4 marks)

Fundamentals of Waves – Science (Physics) 28

Q3. 

A signal generator produces sounds from a loudspeaker. Sound waves travel as longitudinal waves.

Other waves are transverse.(i)  Give an example of a transverse wave.

(1) .............................................................................................................................................

(ii)  Describe how the vibrations of longitudinal waves and transverse waves differ.(2)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

 

(Total for question = 3 marks)

Q4.

Some waves travel across the sea. They all have the same wavelength.

(a) What is meant by the term wavelength?(1)

      .............................................................................................................................................

      .............................................................................................................................................

(b) The waves travel across the sea at 3.0 m/s and have a frequency of 1.5 Hz.(i) State the equation linking wave speed, frequency and wavelength.

(1)

(ii) Calculate the wavelength of the waves.

wavelength ........................................................... m

(2) 

(Total for question = 4 marks)

Fundamentals of Waves – Science (Physics) 29

Fundamentals of Waves – Science (Physics) 30

Q5.  Light travels as a transverse wave.

Some waves travel as longitudinal waves.

(i)  Give an example of a wave that travels as a longitudinal wave.(1)

.............................................................................................................................................

(ii)  Describe the difference between transverse waves and longitudinal waves.

You may draw diagrams to help your answer.(3)

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

.............................................................................................................................................

  (Total for Question = 3 marks)

Fundamentals of Waves – Science (Physics) 31

Q6. 

(a)  The diagram represents a microwave travelling in free space from point A to point B.

(i)  The distance from A to B is 0.60 m.Calculate the wavelength of this microwave.

(2)

wavelength = ........................................... m

(ii)  State the equation linking wave speed, frequency and wavelength.(1)

(iii)  Calculate the frequency of this microwave.[speed of microwave in free space = 3.0 × 108 m/s]

(3)

frequency = ............................................ Hz

 

(Total for question = 6 marks)

Fundamentals of Waves – Science (Physics) 32

Fundamentals of Waves

Spec Point Notes

Fundamentals of Waves Specification Notes

3.01 use the following units: degree (°), hertz (Hz), metre (m), metre/second (m/s) and second (s)

Fundamentals of Waves – Science (Physics) 33

3.02 explain the difference between longitudinal and transverse waves 

3.03 know the definitions of amplitude, wavefront, frequency, wavelength and period of a wave

Fundamentals of Waves – Science (Physics) 34

3.04 know that waves transfer energy and information without transferring matter

3.05 know and use the relationship between the speed, frequency and wavelength of a wave:

wave speed = frequency × wavelength

v = f × λ

Fundamentals of Waves – Science (Physics) 35

3.06 use the relationship between frequency and time period:

time period = 1 ÷ frequency

T=1f

3.07 use the above relationships in different contexts including sound waves and electromagnetic waves

Fundamentals of Waves – Science (Physics) 36

Fundamentals of Waves – Science (Physics) 37