Wave Behaviour (OCR Gateway GCSE Physics)

Topic Questions

1a2 marks

Ultrasound waves can be used to create an image of part of the inside of a body.

Ultrasound waves have a higher frequency than ripples on the surface of water.

Describe another difference between ultrasound waves and ripples on the surface of water.

Explain your answer.

1b5 marks

The graph in Fig. 19.1 shows how displacement of the ultrasound wave varies with distance.


fig-19-1-paper4-oct-nov2020-ocr-gcse-physics

Fig. 19.1

i)
Use the graph in Fig. 19.1 to determine the wavelength of the ultrasound wave.

Wavelength = ....................................................... m [1]

ii)
The speed of ultrasound waves in (b)(i) is 4500 m/s.

Calculate the frequency of the ultrasound wave in Fig. 19.1.

Use the equation: wave speed = frequency × wavelength

Give your answer in standard form and to 2 significant figures.

Frequency = ..................................................... Hz [4]

1c2 marks

Doctors can use an ultrasound scan to measure the size of a person’s kidney.
fig-19-2-paper4-oct-nov2020-ocr-gcse-physics

Fig. 19.2

Complete the sentences using the words below.

Each word may be used once, more than once, or not at all.

Increases Decreases Stays the same


The ultrasound scanner is made from a solid ceramic material.

As the wave enters the body, the speed ................................................. .

As the wave enters the body, the frequency ........................................... .

1d4 marks
i)
Explain what happens to the ultrasound wave when it reaches the kidney.


[2]
ii)
Fig. 19.2 shows the thickness of the kidney, w.

Explain how ultrasound waves are used to measure w.

 [2]

1e1 mark

A doctor uses an ultrasound scan instead of X-rays to measure the kidneys.

Explain why.

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1a4 marks

Ripples are made on the surface of the water. The ripples can be used to model waves.

i)
State the type of wave modelled by the ripples.

 [1]



ii)
Describe how the water molecules move as the wave travels across the pond.


[1]

iii)
10 ripples hit the side of the pond in 20 seconds.
Calculate the frequency of the ripples.

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

1b8 marks

Student A and student B drop stones into a pond.

i)
Student A measures the frequency and wavelength of the water ripples. Table 17.1
shows his results:

Frequency (Hz) of ripples 0.6
Wavelength (m) of ripples 0.1

Table 17.1


         Calculate the wave speed of the ripples.
         Use the equation: wave speed = frequency × wavelength

Wave speed = ...................................................m/s [2]

ii)
Student B measures the same ripples as student A.
She measures:

• The distance one ripple travels.
• The time it takes the ripple to travel this distance.

Table 17.2 shows student B’s results:


Distance ripple travels (m) 2.40
Time taken (s) 30.0

Table 17.2

Name the equipment student B uses to measure the distance and time.

Distance ................................................................

Time .........................................................................


[2] 

iii)
Use results in Table 17.2 to calculate the wave speed of the ripples.

Wave speed = ...................................................m/ s [3]

iv)
Student A and student B obtained different answers for the wave speed of the ripples.
Suggest why.

[1]

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2a4 marks

Look at the diagram of a water wave.

q16-paper2-june2018-ocr-gcse-physics

i)
What is the wavelength of this wave?

Answer = .........................cm [1]

ii)
What is the amplitude of this wave?

Answer = .........................cm [1]

iii)
The wavelength of the wave is changed to 25cm. Two waves are produced each second.

Use the equation: Wave speed = Frequency × Wavelength

Calculate the speed of the wave.

Answer = .........................m/s [2]

2b2 marks

Water waves are transverse and sound waves are longitudinal.

i)
Describe how water particles move in a transverse water wave.

[1]

ii)
Describe how air particles move in a longitudinal sound wave.

[1]

2c4 marks

Look at the diagram of the electromagnetic spectrum.

Radio Microwave Infra-red Visible light Ultra-violet X-rays Gamma-rays



i)
Name a wave that has a longer wavelength than red light.

[1]

ii)
Name a wave that has a higher frequency than violet light.

[1]

iii)
State two uses of gamma-rays.

1 .......................................................................................
2 .......................................................................................

[2]

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3a7 marks

Some students try to measure the speed of sound, as shown in Fig. 24.1.

One student makes a loud sound by clapping her hands.

The sound of the clap reflects from the gym wall causing an echo.

Another student measures the time between hearing the clap and hearing the echo.

fig-24-1-paper4-june2098-ocr-gcse-physics

Fig. 24.1

They repeat the experiment three times and record their results in the table below.

Distance to wall (m) Time 1 (s) Time 2 (s) Time 3 (s) Mean time (s)
50 0.28 0.32 0.54  

i)
The student did not pay attention when recording time 3.

Calculate the mean time taken for the sound of the clap to return, using suitable values from the table.

Mean time taken = ................................ s [1]

ii)
Calculate the speed of sound for the clap.

Use your answer to (a)(i) and the equation: distance travelled = speed × time

Give your answer to 3 significant figures.

Speed of sound = ................................ m/s [4]

iii)
Describe two ways to improve and develop their method.

1 .......................................................................................

2 .......................................................................................

[2]

3b3 marks

Ultrasound wave pulses are used by vets to scan inner tissues inside animals.

The ultrasound pulses partially reflect from different layers of tissue. These reflected wave pulses (echoes) are collected by the detector as shown in Fig. 24.2.

fig-24-2-paper4-june2098-ocr-gcse-physics

Fig. 24.2

In a scan using ultrasound pulses, three layers of tissue are detected, with each layer having a different thickness.

Describe and explain how the results from the detector can show:
•   that there are three layers
•   that each layer has a different thickness.

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4a5 marks

A teacher uses water waves in a ripple tank to demonstrate transverse waves.

q17-paper4-june2018-ocr-gcse-physicsShe makes measurements of the water waves.

The frequency of the water waves is 0.5Hz.

i)
Calculate the number of water waves produced in 5 seconds.

Answer = ......................... [1]

ii)
The teacher increases the frequency of the water waves.

Describe what happens to the speed and the wavelength of the water waves.

[2]

iii)
A student tries to describe water waves in the sea.

‘The water waves move up and down. The water particles move all the way across the surface of the sea. This means that water moves in the direction of the waves.’

Part of his explanation is incorrect.

Write an improved and correct description about water waves in the sea.

[2]

4b5 marks

A student watches a ball game on the school field.

The student sees the ball being hit with a bat but he hears the sound a short time after. This is because the speed of light is much greater than the speed of sound.

Describe an experiment which measures the speed of sound in air.

In your answer describe the measurements, calculations and procedures needed to gather accurate and reliable results.

You may draw a diagram as part of your answer.

4c3 marks

Higher Only

 

Look at the diagram of a human ear.
q17c-paper4-june2018-ocr-gcse-physicsSound wave disturbances, outside the ear, transfer energy to the small hairs (cilia) inside the cochlea.

The cochlea then sends nerve impulses along the auditory nerve to the brain.

Explain how sound wave disturbances in the air outside the ear transfer to the small hairs (cilia) inside the cochlea.

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5a1 mark

A crowd makes a Mexican wave.

A Mexican wave starts with people lifting and lowering their arms.
q16a-paper4-specimen-ocr-gcse-physicsThe Mexican wave continues by people, next to them, lifting and lowering their arms.

Why is a Mexican wave an example of a transverse wave?

5b5 marks

In the classroom a teacher demonstrates waves using a rope.

Look at the diagram of the wave.

q16b-paper4-specimen-ocr-gcse-physics

i)
The frequency of the wave is 2 Hz.

What does this statement mean?

[2]

ii)
How many seconds will it take for this wave to travel 12 m?

Show your working.

Answer = ......................... seconds [3]

5c3 marks

Higher Only

 

Ultrasound scans are used to produce images of tissues inside the body.

q16c-paper4-specimen-ocr-gcse-physics

Ultrasound waves are emitted.

The waves reflect from layers of tissue inside the body.

Explain how the reflections are used to produce an image of the tissues.

5d3 marks

Ultrasound and X-rays are used to scan patients in hospitals.

Complete the table to show a medical use, benefits and risk of using these waves to scan patients.

Wave Medical use

Example of a

benefit

Risk
X-rays Shows up hard
tissues inside the
body.
Takes images of
broken bones

Damages living
cells by causing:

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

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

Ultrasound

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

............................ ............................  None

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6a3 marks

Fig. 20.1 is a graph of a wave.

fig20-1-paper2-june2098-ocr-gcse-physics

Fig. 20.1

i)
Use the graph in Fig. 20.1 to work out the time period of the wave.


Time period of the wave = ................................ s [1]

ii)
Use the graph in Fig. 20.1 to work out the amplitude of the wave.


Amplitude = ................................ cm [1]

iii)
The frequency of the wave in Fig. 20.1 is 0.5 Hz.

What is meant by the term frequency?

[1]

6b3 marks

A water wave has a frequency of 0.25 Hz and a wavelength of 6.0 m.

Calculate the speed of the wave.


Speed of the wave = ................................ m/ s [3]

6c3 marks

Surface water waves can be modelled using a slinky spring.

A student holds one end of the spring on a table. The other end is fixed to a wall.

Fig. 20.2 shows the spring viewed from above the table.

fig20-2-paper2-june2098-ocr-gcse-physics

Fig. 20.2

i)
Draw two arrows on the diagram in Fig. 20.2 to show the movement of the student’s hand when he makes a transverse wave.
[1]

ii)

Describe what happens to the transverse wave at the wall.

 [1]

iii)
In Fig. 20.3 the student stops moving his hand.

         This is what the coils in the spring look like after a short time:

fig20-3-paper2-june2098-ocr-gcse-physics

Fig. 20.3

This model of a water wave shows that the wave travels not the water.

Explain why.

[1]

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