P3 02 Ultrasound

142 minutes

142 marks

Q1.          The diagram shows an ultrasound monitor being used to scan a fetus.

          The table shows the velocity of ultrasound waves in different tissues of the fetus.

 

Tissue Velocity of ultrasound in m/s

Amniotic fluid(liquid surrounding fetus)

1540

Bone 3080

Kidney 1561

Liver 1549

Muscle 1585

          Explain why we are able to see the different parts of the fetus in an ultrasound scan. You may use information from the table in your answer.

          To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words.

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Q2.          The table gives the frequencies of sound that different animals can hear.

 

Animal Lowest frequency it can hear in Hz

Highest frequency it can hear in Hz

Human 64 23 000

Dog 67 45 000

Mouse 1 000 91 000

Rat 200 76 000

Cat 45 64 000

Tuna 50 1 100

Canary 250 8 000

Chicken 125 2 000

(a)     (i)      Which animal can hear the lowest sound frequency?

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(ii)     Which animal can hear the smallest range of frequencies?

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(b)     (i)      What is the name given to sound frequencies higher than those that humans can hear?

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(ii)     Give one industrial use of this type of sound.

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(Total 4 marks)

 

 

Q3.          Pigs have a layer of fat in their skin. Underneath the fat is a layer of muscle. Ultrasonic waves are used to measure the thickness of the layer of fat. An ultrasound transmitter and detector are attached to the skin of the pig.

(a)     Explain why ultrasound can be used to measure the thickness of the layer of fat.

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(b)     The oscilloscope does not measure distance directly.

(i)      What does the oscilloscope measure in this case?

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(ii)     What other information is needed to calculate the thickness of the layer of fat in a pig?

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(Total 4 marks)

 

 

Q4.          The diagram shows how ultrasonic waves can be used to clean a watch.

          Suggest how this method cleans the watch.

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Q5.          (a)     Complete the following sentence:

          Sound is produced when an object ...............................................(1)

(b)     Choose words from the list to complete the following sentences:

higher                  louder         lower          quieter

(i)      If the frequency is increased, the pitch of the sound becomes ........................

(ii)     If its amplitude is increased, the sound becomes ............................................(2)

(c)     The diagram shows a pre-natal scan.

(i)      What type of waves are used for pre-natal scanning?

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(ii)     Explain why we cannot hear these waves.

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(Total 6 marks)

 

 

Q6.          (a)     Sound travels through air, water and glass at different speeds. Through which of these materials does sound travel:

          the fastest; .............................................

          the slowest? ...........................................(2)

          Give a reason for your choice of answers.

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(b)     The bar chart shows the frequencies of sound which different animals can make and can hear.

(i)      Which of the animals can make sounds which are beyond their own hearing range?

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(ii)     What name is given to the sounds which a cat can hear but a human cannot?

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(c)     The diagram shows a trawler searching for a shoal of fish. Pulses of high frequency sound emitted from the trawler are reflected back to the trawler. The pulses are displayed on a cathode ray oscilloscope.

          Complete the diagram below to show the pattern seen on the cathode ray oscilloscope as the trawler passes over the shoal of fish.

(2)(Total 7 marks)

 

 

Q7.          (a)     An endoscope is an instrument used by doctors for looking inside patients. A bundle of thin optical fibres pass light into the patient’s body, a second bundle of fibres carry reflected light back to the doctor.

(i)      Complete the diagram below to show how an optical fibre is able to pass light into a patient’s body.

(2)

(ii)     Give one advantage of using lots of thin fibres to make the bundles, rather than a few thick fibres.

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(iii)     Give one further example of the practical use of an optical fibre.

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(b)     The diagram shows a wave travelling through a stretched spring.

In what way is this wave the same as a sound wave?

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(1)

(c)     Sound waves travel faster in liquids than in gases. Why?

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(d)     A bat uses ultrasound to find its way around. Explain how.

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(Total 8 marks)

 

 

Q8.          (a)     What is ultrasound?

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(b)     The picture shows a pregnant woman having an ultrasound scan and the image produced by the scan.

          To produce the image, a very narrow beam of ultrasound pulses is fired into the mother’s body. The reflected pulses are used to build up the image of the unborn baby.

(i)      Why is it important to have a very narrow beam of ultrasound waves?

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(ii)     Why is it possible to produce a very narrow beam with ultrasound but not with normal sound waves?

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(iii)     The image produced by ultrasound is not as clear as an image produced by X-rays. Why is ultrasound used for looking at unborn babies rather than X-rays?

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(iv)    Give two important pieces of information about an unborn baby which can be gained from the image produced by an ultrasound scan.

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

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

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(Total 6 marks)

 

 

Q9.          (a)     A microphone connected to an oscilloscope picks up the sound from a siren. The trace produced on the oscilloscope screen is shown below.

          Describe how the wave changes as it goes across the screen from left to right (→).

          To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words.

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(b)     An African bat produces a sound wave with a frequency of 212 kHz and a wavelength of 0.0016 m.

(i)      The sound made by the bat is above the limit of human hearing.What name is given to this type of sound?

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(ii)     Write down the equation that links frequency, wavelength and wave speed.

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(iii)     Calculate the speed of this sound wave through the air. Show clearly how you work out your final answer.

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Wave speed = ............................... m/s(3)

(Total 8 marks)

 

 

Q10.          The picture shows a pre-natal scan obtained using ultrasonic waves.

(i)      Explain how ultrasonic waves are used to produce the image of an unborn baby.

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(ii)      Give another use for ultrasonic waves.

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(Total 3 marks)

  

Q11.          Ultrasound can be used in industry for detecting internal cracks in metals.

(a)     State two features of ultrasound.

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

2 ..................................................................................................................................(2)

(b)     The diagram shows an ultrasound transmitter and detector fixed to the front of a metal block. The block has an internal crack.

          The diagram below shows the screen of the oscilloscope connected to the detector.

(i)      Explain why pulse A and pulse B occur.

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(ii)     The metal block is 120 mm from front to back. What is the distance, in mm, from the front of the block to the internal crack?

Distance = .................... mm(1)

(Total 5 marks)

 

 

Q12.          (a)     A student uses a microphone to send different sounds to an oscilloscope. The diagrams show five traces, A, B, C, D and E, on the oscilloscope. All the traces are drawn to the same scale.

(i)      Which three diagrams show traces with the same amplitude?

Diagrams .......... , .......... and .......... .(1)

(ii)     Which two diagrams show traces with the same frequency?

Diagrams .......... and .......... .(1)

(b)     The diagram shows the sound frequencies which some living things can hear.

(i)      What is the widest range of frequencies that a human child can hear?

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(ii)     Why can some dog whistles be heard by dogs but not by humans?

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(c)     An ultrasound scan can be used to make a picture of a baby in its mother’s womb. An ultrasound transmitter and detector are placed above the mother’s womb. Ultrasound goes into the body of the mother and into the body of the baby.

          

Use the correct words from the box to complete the sentences.

detector     reflection       refraction       sound          substance      transmitter

(i)      When the ultrasound crosses from one ................................................. to another,

some ultrasound becomes an echo caused by ................................................. .

(ii)     This information is collected by the ultrasound .................................................

and made into a picture on a screen.(3)

(Total 7 marks)

 

 

Q13.          (a)     The diagrams show oscilloscope traces for the same musical note played on twodifferent instruments. The oscilloscope settings are not changed.

                 

(i)      How can you tell, from the diagrams, that it is the same musical note?

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(ii)     How can you tell, from the diagrams, that the musical note has been played on different instruments?

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(b)     This passage is from an electronics magazine. 

Electronic systems can be used to produce ultrasound waves.These waves have a higher frequency than the upper limit for hearing in humans.Ultrasound waves are partially reflected when they meet a boundary between two different media.

(i)      Approximately what is the highest frequency that humans can hear?

         State the number and the unit.

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(ii)     What does the word media mean when it is used in this passage?

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(iii)     What happens to the ultrasound which reaches the boundary between two different media and is not reflected?

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(Total 6 marks)

 

 

Q14.          (a)     This information is from a science magazine.

 

Electronic systems can be used to produce ultrasonic waves.

These waves have a frequency higher than the upper limit for hearing in humans.

          Complete the sentence by choosing the correct number from the box.

 

             20                    2000                 20 000                200 000

          The upper limit for hearing in humans is a frequency of ............................................ Hz.(1)

(b)     An electronic system produces ultrasound with a frequency of 500 kHz.

          What does the symbol kHz stand for?

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(c)     (i)      State one industrial use for ultrasound.

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(ii)     State one medical use for ultrasound.

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(d)     An ultrasound detector is connected to an oscilloscope.

          The diagram shows centimetre squares on an oscilloscope screen. Each horizontal division represents 2 microseconds.

          Calculate the time, in microseconds, between one peak of one ultrasound pulse and the peak of the next.

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Time = .............................. microseconds(1)

(e)     Ultrasounds are partially reflected when they reach a boundary between two different media.

          The time taken for the reflection from the boundary to reach the detector can be seenfrom the screen.

          What can be calculated from this time interval?

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(f)      Explain what action scientists should take if they find evidence that ultrasonic waves may be harmful to human health.

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(Total 9 marks)

 

 

Q15.          (a)     Explain what an ultrasound wave is.

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(b)     Ultrasound waves can be used to clean jewellery.

One method is to put the jewellery in a bath of cleaning fluid which contains an electronic oscillator. The electronic oscillator generates ultrasound waves in the cleaning fluid.

Suggest how these waves clean the jewellery.

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(c)     Ultrasound is used for pre-natal scanning. This is much safer than using X-rays. However, doctors were only sure it was safe after experiments on mice.

Explain whether or not you think that these experiments were justified.

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(Total 6 marks)

 

 

Q16.          A group of students investigates sound waves.

The diagram shows part of their investigation.

(a)     Identify the equipment labelled A.

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(b)     The student plays the same note in the same way at different distances from equipmentA.

Another student records the amplitude of the wave shown on the cathode ray oscilloscope (CRO).

(i)      Label this wave to show its amplitude.

(1)

(ii)     Complete the sentence.

Increasing the amplitude of a sound wave will increase the ..........................

of the sound.(1)

(c)     The graph shows the students’ average results from several sets of measurements.

Use the graph to find the distance, d, in centimetres, at which the average amplitude is likely to be 2 centimetres.

                                                  Distance = ............................................ cm.(1)

(d)     Write a conclusion for this investigation.

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(e)     A physics teacher uses a signal generator and a loudspeaker to demonstrate the range of hearing of a group of students.

What is the range of frequencies most humans can hear?

Most humans can hear from .............................. Hz to .............................. Hz.(2)

(Total 7 marks)

 

 

Q17.          Ultrasound waves are very high frequency sound waves. They cannot be heard by humans.

(a)     Ultrasound waves can be used to clean jewellery.

The jewellery is put into a container of cleaning fluid.

Complete each sentence to explain how ultrasound can clean jewellery.

The ultrasound generator makes the molecules of the cleaning fluid

............................... . The molecules knock particles of ................................

from the surface of the jewellery.(2)

(b)     Give a medical use for ultrasound.

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(c)     Ultrasound waves can be represented on the screen of a cathode ray oscilloscope (CRO).

The diagrams show three ultrasound waves.Each wave is represented on an identical CRO screen, A, B and C.

 

Screen A Screen B Screen C

(i)      How many complete waves are shown on screen B? ..........................(1)

(ii)     Which screen shows the waves with the highest frequency?

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

(Total 5 marks)

 

 

Q18.          The diaphragm of a loudspeaker moves in and out.

A team of scientists investigated loudspeakers.

The scientists measured the size of the movement of the diaphragm for signals of different frequencies.They kept all the other variables constant.The graph shows the average results for a large number of tests on one of the loudspeakers.

(a)     What is the frequency of the highest pitched sound which this loudspeaker produces?

                                 Frequency = ................................................... Hz(1)

(b)     The greater the movement of the diaphragm, the greater the amplitude of the sound produced.

What is the frequency of the loudest sound which this loudspeaker produces?

Show clearly on the graph how you get to your answer and then complete this answer space.

                                 Frequency = ................................................... Hz(2)

(c)     Can this loudspeaker produce the full range of sound which most people can hear?

Put a tick ( ) in the box next to your answer.

Yes                                            No        

Explain the reason for your answer.

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(d)     Use one word to complete the sentence.

Repeating tests a large number of times and taking the average of the results

improves the ......................................................... .(1)

(e)     Why did the scientists keep all the other variables constant?

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(Total 7 marks)

 

 

Q19.          (a)     The diagram shows a microphone being used to detect the output from a loudspeaker.The oscilloscope trace shows the wave pattern produced by the loudspeaker.

(i)      How many waves are produced by the loudspeaker in 0.0001 seconds?

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(ii)     How many waves are produced by the loudspeaker every second?Assume the input to the loudspeaker does not change.

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(iii)    A person with normal hearing cannot hear the sound produced by the loudspeaker.

Explain why.

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(b)     The diagram shows how a very high frequency sound wave can be used to check for internal cracks in a large steel bolt. The oscilloscope trace shows that the bolt does have an internal crack.

(i)      Explain what happens to produce pulse A and pulse B.

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(ii)     Use the information in the diagram and the equation in the box to calculate the distance from the head of the bolt to the internal crack.

 

distance    =    speed    ×    time

Speed of sound through steel = 6000 m/s

Show clearly how you work out your answer.

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(Total 9 marks)

 

 

Q20.(a)     The diagram shows four sound waves, J, K, L and M, represented on an oscilloscope screen.

They are all drawn to the same scale. 

J K L M

(i)      Which two of the waves have the same amplitude?

Wave ...................... and wave ......................(1)

(ii)     Which of the waves would sound the loudest?

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

(iii)    Only one of the waves is an ultrasound wave.

Which one is the ultrasound wave?

Wave ......................

Give a reason for your answer.

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(b)     The diagram shows ultrasound being used to examine the ligament inside the leg of a horse.

Use words from the box to complete the following sentences. 

computer detector transmitter

The ....................................... sends pulses of ultrasound into the leg. When the

ultrasound meets the ligament, some is reflected back to the ............................

The reflected pulses are converted by a .......................... into an image that can

be seen on the screen.(2)

(Total 6 marks)

 

 

Q21.(a)    Explain what ultrasound is.

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(b)     Ultrasound is used for pre-natal scanning. This is much safer than using X-rays. However, doctors were only sure ultrasound was safe after experiments on mice.

Do you think the ultrasound experiments on mice were justified?

Explain your answer.

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(c)     Explain what scientists should do if they find evidence that ultrasound may be harmful to human health.

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(Total 6 marks)

Q22.Ultrasound and X-rays are waves used in hospitals to create images of the inside of the human body. To produce the images below, the waves must enter the human body.

      Ultrasound scan of an unborn child                     X-ray of a broken bone

 © Isabelle Limbach/Thinkstock                           © itsmejust/iStock

(a)     In this question you will be assessed on using good English, organising information clearly and using specialist terms where appropriate.

Describe the features of ultrasound and X-rays, and what happens to each type of wave after it has entered the human body.

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(b)     It would not be safe to use X-rays to produce an image of an unborn child.

Explain why.

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(c)     Ultrasound can be used for medical treatments as well as for imaging.

Give one use of ultrasound for medical treatment.

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(Total 9 marks)

Q23.(a)     Human ears can detect a range of sound frequencies.

(i)      Use the correct answers from the box to complete the sentence. 

  2 20 200 2000 20 000

 

The range of human hearing is from about ...................... Hz to ...................... Hz.(2)

(ii)     What is ultrasound?

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(iii)    Ultrasound can be used to find the speed of blood flow in an artery.

State one other medical use of ultrasound.

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(b)     The speed of an ultrasound wave in soft tissue in the human body is 1.5 × 103 m / s and the frequency of the wave is 2.0 × 106 Hz.

Calculate the wavelength of the ultrasound wave.

Use the correct equation from Section B of the Physics Equations Sheet.

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Wavelength = ........................................ m(2)

(c)     When ultrasound is used to find the speed of blood flow in an artery:

•        an ultrasound transducer is placed on a person’s arm

•        ultrasound is emitted by the transducer

•        the ultrasound is reflected from blood cells moving away from the transducer

•        the reflected ultrasound is detected at the transducer.

Describe the differences between the ultrasound waves emitted by the transducer and the reflected waves detected at the transducer.

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(Total 8 marks) 

M1.          Quality of written communication

          correct use of three scientific terms from speed / velocity, reflection,density, time, boundary1

          any three from:

          different tissues have different densities

          ultrasound travels at different speeds / velocities in different tissues

          reflectionaccept bouncing back

          from tissue boundaries

          time taken to return3

[4]

 

 

M2.          (a)     (i)      cat1

(ii)     tuna1

(b)     (i)      ultrasoundallow ultrasonic

1

(ii)     cleaning / quality control / flaw detection / medical scanning /animal scaring / sonar

1[4]

 

 

M3.          (a)     (ultrasound) waves reflectedaccept ‘bounce off’

1

          at boundary / from muscle1

(b)     (i)      time1

(ii)     speed of (ultrasound) waves1

[4]

 

 

M4.          (ultrasonic) waves or vibrations or oscillations in fluidN.B. must mention fluid or liquidor water

1

          idea of shaking dirt particles off watchallow cavitation / implosion of small bubbles

1[2]

 

 

M5.          (a)     vibrates (owtte)for one mark

1

(b)     (i)      higherfor one mark

1

(ii)     louderfor one mark

1

(c)     (i)      ultrasonic (ultrasound)for one mark

1

(ii)     different frequency / wavelength / pitchgains 1 mark

         buthigh frequency / pitch, higher frequency /pitch (lower frequency / pitch wrong)

gains 2 marks2

[6]

 

 

M6.          (a)     glass1

          airmust be in correct order

1

closer the particles faster the speedanswer must show a comparison

or

          particles in glass closest in air furthest apartaccept the denser the material the faster the sound travels

or

          sound travels faster in solids than gasesincorrect explanation negates credit

1

          (b)     (i)      grasshopper

(ii)     ultrasoundaccept ultrasonic

1

(c)     all of reflected pulse closer than given in original diagramaccept a cluster of pulses ignore a reflected pulse in original position any pulse drawn to right of original negates credit

1

          reflected pulse smaller than emitted but greater than 1 square highaccept cluster of pulses provided one part fulfils height criteria

2[7]

 

 

M7.          (a)     (i)      total internal reflection shown (2 – 8 reflections)1

angles look correct (by eye) (2 – 5 reflections)1

(ii)     can be bent more (without loss of light)accept easier to get into patient or more flexibleaccept more detailed or better imageaccept if some fibres broke system would not faildo not accept to pass more light - neutral

1

(iii)     any one of the following:

do not accept any further endoscopy uses

         (telephone) communications (carry (laser) light) for surgeryor operationstorchesguides in carstable lamps or ornamental lights

do not accept telephone wires1

         carry TV signalscarry computer data or information cable TV or cable telephone

do not accept TV or telephone or computers without qualificationdo not accept bomb disposal unless qualifiedaccept to stimulate children with learning difficulties

(b)     (both) longitudinalaccept both have compressions or rarefactionsaccept both have high or low pressure regionsaccept both transfer energydo not accept 'need a medium'

1

(c)     liquids have a greater density

or

molecular spacing in gases is greater1

(d)     (bat) transmits or emits ultrasound or pulses or signals or sound or wavesallow one mark if response is in terms of distance and time

1

picks up reflected ultrasound or signals or waves or sound or echoallow 1 mark for echo location

1[8]

 

 

M8.          (a)     sound with a frequency above audibledo not accept answer in terms of λdo not accept sound which cannot be heard unless obvious from contextaccept above 20 kHz

1

          (b)     (i)      to show detail or to give a clear image/pictureaccept the generators or transducers can be smallaccept so the beam does not spread out/beam in focus

not ‘good picture’1

(ii)     (much) smaller wavelengthallow higher frequency/pitch

1

(iii)     no damage to living cells (provided low power)accept the converseaccept no damage to baby or not dangerous to baby

1

(iv)    any two forms

sex

stage of developmentor specific examples

abnormalities

general health

potential problems (at birth)accept specific examples e.g. umbilical cord around neck

size of headaccept multiple births

2[6]

 

 

M9.          (a)     any two from:

•        amplitude decreasingaccept siren / sound getting quieterdo not accept sound decreases

•        wavelength increasing

•        frequency decreasingaccept pitch decreasingignore reference to transverse waveignore reference to speedcontradictory statements within each point lose the mark

2

          Quality of written communicationall emboldened terms in candidate’s answer used correctly

1

(b)     (i)      ultrasound or ultrasonic1

(ii)     wave speed = frequency × wavelengthaccept speed / velocity for wave speedaccept v = f   λdo not accept w for λdo not accept s for vaccept

 provided subsequent calculationshows a correct method

1

(iii)     339.2 or 340 or 339allow 1 mark for using 212 000allow 1 mark for correct substitutionan answer of 0.3392 or 0.34 or 0.339 gains 1 mark onlyaward full credit for a correct numerical answer with the unit changed to km/s

3[8]

 

 

M10.          (i)      (partly) reflected when they hit a (boundary between two) different mediaor substance or tissue

accept named substancesdo not accept bounce back

1

         time taken for reflected wave (to return) is used to produce the image1

(ii)      any one from:

          cleaning a delicate mechanism / jewellerydo not accept cleaning

          welding plastics

          cutting textiles

          mixing emulsion paints

          sonar

          motion sensors (in burglar alarms)

do not accept burglar alarms

          removing dental plaque

          industrial quality control

          breaking up kidney stones

          treating injuries1

[3]

  

M11.          (a)     any two points:do not credit features which are true of sound in general eg longitudinal waves

•        humans cannot hear ultrasound

•        it has a very high frequency / pitchdo not credit just ‘has a high frequency / pitch’

•        above the (upper) limit for humans / above 20 000 Hz2

(b)     (i)      ultrasound / waves are reflected...are bounced is insufficient, but...echo is acceptable

1

         Pulse A indicates / is the crack

         Pulse B indicates / is the back (of the block or crack)need to mention both A and B to get this mark

1

(ii)     90 (mm)accept any answer in the range 88 – 92 (mm)

1[5]

 

 

M12.          (a)     (i)      A, C and Dany order but all three required and no others

1

(ii)     D and Eeither order but both required and no others

1

(b)     (i)      20000 (Hz) to 20 (Hz)accept ‘19980 (Hz)’

         or vice-versa1

(ii)     frequency (of dog whistle) too high (for humans to hear) / frequencyabove 20000 Hz

accept ‘it is ultrasound’accept ‘sound from the whistle is ultrasonic’

1

(c)     (i)      substance1

         reflectioncorrect order essential

1

(ii)     detector1

[7]

 

 

M13.          (a)     (i)      same frequency / period / pitch / wavelengthignore references to amplitude

1

(ii)     differences in waveform / shape / qualityaccept the diagrams are not identical

1

(b)     (i)      20 000 Hz / hertz

         or 20 kHz / kilohertzin both cases, if the symbol rather than the name is used, it must be correct in every detail

1

(ii)     material(s) / substance(s) (through which sound travels)1

(iii)     is absorbedaccept (some) sound (energy) is transformed / transferred as heat / thermal energy

1

         is transmittedaccept is refracted

accept changes speedaccept changes velocitydo not accept is diffracteddo not accept is diffuseddo not accept is dissipated

1[6]

 

 

M14.          (a)     20000accept any unambiguous indication

1

(b)     kilohertzcredit misspellingscredit ‘1000 hertz’ or ‘1000 Hz’accept 1000 oscillations/beats/waves per second

1

(c)     (i)      cleaning (e.g. something delicate such as a watch)or quality control/flaw detectioncredit any appropriate extra Specification responsee.g. sonar

1

(ii)     pre-natal (scanning)do not credit just ‘scanning’/medical scanning/ scanning a babycredit any appropriate extra Specification responsee.g. destruction of (kidney) stones or cleaning teeth

1

(d)     8 (μs)1

(e)     distance (1)

          between the boundary and the detector (1)accept ‘between the boundary and the source’accept any correct use of speed = distance/time

2

(f)      examples

          publish/tell doctors/the public (1) ... their evidence/results/research/data (1)

          carry out more research/tests (1) ... to make sure/check reliability (1)allow a wide variety of appropriate responsesvalid point (1) appropriate example/qualification/expansion/etc. (1)allow just ‘stop using them/ultrasonic waves’ (1)

allow using them (only) for industrial purposes (1)2

[9]

 

 

M15.          (a)     sound / mechanical / longitudinal (wave )1

any one from:

•        above 20 000 hertz / 20kHz

•        above (human) audible range

•        cannot be heard by humans1

(b)     either

particles / molecules / fluid vibrate(s) (1)

(and) knock particles of dirt off the jewellery (1)

or

by the process of cavitation (1)accept ‘formation and collapse of tiny bubbles’

which breaks up / releases dirt from the surface (1)2

(c)either both proor both conor one of each

either

two appropriate points gain 1 mark each

or

one appropriate point (and) appropriate qualification / amplificationexamplesother mammals (sufficiently) similar to humans (1)so results appropriate (1)unethical to experiment on humans (1)so it is better to experiment on mice (1)knowledge / techniques will benefit humans (1)and also other animals (1)

experiments were justified because ultrasound has proved useful (1)

2[6]

 

M16.          (a)     microphone1

(c)     (i)      vertical line from any maxima or minima to axisdo not penalise minor errors butdo not allow unless intention is clear

1

(ii)     loudness / volume / intensity / energydo not accept noise

1

(c)     17this answer only

1

(d)     the greater the distance, the smaller the amplitudeaccept volume / intensity / energy / loudness for amplitude

orthere is a (strong) negative correlation between distance and amplitudeorthere is an inverse square relationship between distance and amplitude

do not accept distance and amplitude are inversely proportional1

(e)     20 Hzeither order

1

20,000 Hzaccept 20 kHz provided unit has been clearly changed

1[7]

 

M17.          (a)     vibrateallow move more (vigorously) but not just move

1

dirt / muck / grit / rust / dust etc.do not accept bacteria

1

(b)     any one medical use egignore incorrect biological detail

•        scanning unborn babies

•        destroying (kidney) stones1

(c)     (i)      21

(ii)     C1

[5]

 

M18.          (a)     10 600 (Hz)accept 10.6 kHz

1

(b)     3000 (Hz)allow 1 mark for a line drawn to show greatest movement(allow only if frequency is between 2800 and 3200)accept other indication of correctly using the graph

2

(c)     (No)no marks for just the ticked boxreasons can score even if yes is ticked

(human hearing) range is 20 – 20 000 (Hz)accept (most) people hear up to 20 000 (Hz) / 20 kHz

1

any one from:

•        range on graph is within this range

•        range on graph starts after 20 Hz

•        range on graph is from to 200 – 10 600 (Hz)

•        range on graph finishes before 20 000 Hz1

(d)     reliabilitythis answer only

1

(e)     only 1 variable affects dependent variable / size of movementaccept ‘results’ for ‘size of movement’

orthere is only one independent variable

fair test is insufficientdo not accept to control the experiment

orto be able to compare (effect of different frequencies)

1[7]

 

M19.         (a)      (i)     31

(ii)     30 000 or 10 000 × their (a)(i) correctly calculated1

(iii)    any two from:

•    frequency is above 20 000 (Hz)accept the frequency is 30 000

•    frequency is above the upper limit of audible range

•    upper limit of audible range equals 20 000 (Hz)ignore reference to lower limit

•    it is ultrasound/ultrasonic2

(b)     (i)      wave (partially) reflected1

at crack to produce A and end of bolt to produce Baccept at both ends of the crack

1

(ii)     0.075 (m) allow 2 marks for time = 0.0000125

allow 1 mark for time = 0.000025answers 0.15 or 0.015 or 0.09 gain 2 marksanswers 0.18 or 0.03 gain 1 markthe unit is not required but if given must be consistent with numerical answer for the available marks

3[9]

 

M20.         (a)      (i)     J and Lboth required, either order

1

(ii)     K1

(iii)    L1

highest frequencyreason does not score if L not chosenaccept most waves (on screen)do not accept frequency above 20 000(Hz)do not accept cannot hear it

1

(b)     transmitter

detector

computerall three in correct orderallow 1 mark for one correct

2[6]

 

M21.(a)     any two from:

•         (sound with frequency) above 20 000 hertz / 20 kHz

•         frequencies above (human) audible range

•         (sound) cannot be heard by humans2

(b)     either 

two appropriate points gain 1 mark eacheither both pro / con or one of each

orone appropriate point (and) appropriate qualification / amplification

examples other mammals (sufficiently) similar to humans (1)so results appropriate (1)unethical to experiment on humans (1)so it is better to experiment on mice (1)knowledge / techniques will benefit humans (1)and also other animals (1)experiments were justified because ultrasound has proved useful (1)

2

(c)     examplesallow a wide variety of appropriate responses

publish / tell doctors / the public (1)…their evidence / results / research / data (1)valid point (1)appropriate example / qualification / expansion / etc (1)

carry out more research / tests (1) …to make sure / check reliability (1)allow just ‘stop using them / ultrasonic waves’ for 1 mark onlyallow using them (only) for industrial purposes for 1 mark only

2[6]

M22.(a)     Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response. Examiners should also refer to the information in the Marking guidance, and apply a ‘best-fit’ approach to the marking.

0 marksNo relevant / correct content.

Level 1 (1-2 marks)There is a basic description of either waveORWhat happens to either wave when they enter the body. However there is little other detail.

Level 2 (3-4 marks)There is either:A clear description of BOTH wavesORA clear description as to what happens to BOTH waves inside the bodyORA clear description of ONE of the waves with clear detail as to what happens to either wave inside the body.

Level 3 (5-6 marks)There is a detailed description of BOTH of the wavesANDA detailed description as to what happens to EITHER wave inside the body.

Examples of the points made in the response:

Description of an X-ray

•         X-rays are electromagnetic waves / part of the electromagnetic spectrumdo not allow a description of a property – eg X-rays travel

•         X-rays are (very) high frequency (waves)through a vacuum / at the speed of light

•         X-rays are (very) high energy (waves)

•         X-rays have a (very) short wavelength

•         Wavelength (of X-rays) is of a similar size to (the diameter of) an atom

•         X-rays are a transverse wavecorrect description acceptable – oscillations / vibrations are perpendicular (at 90°) to direction of energy transfer

•         X-rays are ionising radiation

Description of ultrasound

•         ultrasound has a frequency above 20 000 (hertz)

or

ultra sound is above 20 000 hertz

•         ultrasound is above / beyond the human (upper) limit (of hearing)accept ultrasound cannot be heard by humans

•         ultrasound is a longitudinal wavecorrect description acceptable – oscillations / vibrations (of particles) are parallel (in same direction) to direction of energy transfer

Statement(s) as to what happens to X-rays inside the human body:

•         X-rays are absorbed by bone

•         X-rays travel through / are transmitted by tissue / skin

Statement as to what happens to ultrasound inside body:

•         ultrasound is (partially) reflected at / when it meets a boundary between two different media

•         travel at different speeds through different media6

(b)     (because the X-rays) are ionisingaccept a description of what ionising is

1

(they will) damage cellsinstead of cell, any of these words can be used:DNA / genes / chromosomes / nucleus

or

mutate cells / cause mutations / increase chances of mutations

or

turn cells cancerous / produce abnormal growths / produce rapidly growing cellsdo not accept they can be dangerous (to human health)do not accept damage to soft tissue

or

kill cells1

(c)     any one from:

•         removal / destruction of kidney / gall stones

•         repair of damaged tissue / muscleaccept examples of repair, eg alleviating bruising, repair scar damage, ligament / tendon damage, joint inflammationaccept physiotherapyaccept curing prostate cancer or killing prostate cancer cells

•        removing plaque from teethcleaning teeth is insufficient

1[9]

M23.(a)     (i)      201

20 000either orderaccept ringed answers in box

1

(ii)     (frequency) above human rangeaccept pitch for frequency

or

(frequency) above 20 000 (Hz)do not accept outside human rangeallow ecf from incorrect value in (a)(i)

1

(iii)    any one from:

•        pre-natal scanningaccept any other appropriate scanning usedo not accept pregnancy testing

•        removal / destruction of kidney / gall stones•        repair of damaged tissue / muscle

accept examples of repair, eg alleviating bruising, repair scar damage, ligament / tendon damage, joint inflammationaccept physiotherapyaccept curing prostate cancer or killing prostate cancer cells

•        removing plaque from teethcleaning teeth is insufficient

1

(b)     7.5 × 10−4 (m)1.5 × 103 = 2.0 × 106 × λ gains 1 mark

2

(c)     for reflected wavesmust be clear whether referring to emitted or detected / reflected wavesif not specified assume it refers to reflected wave

any two from:

•        frequency decreased•        wavelength increased•        intensity has decreased

allow amplitude / energy has decreasedallow the beam is weaker

2[8]

 

E1.          This question was very poorly answered by the majority of candidates. Many had the idea that different speeds of ultrasound are used to identify different tissues. Few explained that partial reflection, caused at a boundary between tissues of different densities, enabled time to be measured. The Quality of Written Communication mark was rarely awarded, candidates failing to use the terms described above.

 

 

E2.          (a)     Most candidates could extract at least one correct figure from the table.

(b)     In part (i) the term ultrasound or ultrasonic was not known by many. Examiners saw several references to supersonic and even a few to ‘panasonic’. In (ii) some candidates were confusing ultrasound with microwaves, which led them to giving answers concerning radar.

 

 

E3.          Ultrasound still tends to confuse most candidates.

(a)     Those who read and applied the information in the introduction to the question, scored best. These candidates realised that some ultrasound waves would be reflected from the layer of muscle underneath the fat. Weaker candidates ignored this information and answered in terms of ante-natal pictures.

(b)     Many realised that the oscilloscope measures time, but only the most able candidates realised that wave-speed was needed in (ii).

 

 

E4.          Foundation Tier

          This proved to be probably the most difficult question on the paper for the foundation tier candidates.

          The better ones realised that waves travelled through the fluid (which was often thought erroneously to be water). However, hardly any candidates appreciated how these waves could then dislodge the dirt particles. It was common to see reference to the waves dissolving the dirt or killing bacteria on the watch.

          Higher Tier

          The better candidates realised that waves travelled through the fluid (which was often thought erroneously to be water). However, surprisingly few appreciated how these waves could then dislodge the dirt particles. It was common to see reference to the waves dissolving the dirt or killing bacteria on the watch.

 

 

E5.          Parts (a) and (b) were well answered by most candidates.

          In part (c)(i) only a minority managed "ultra-sound" to gain the mark, the common distractor was

"ultra-violet". In part (c)(ii) many candidates gained the mark for increased pitch or frequency, the more able often went far beyond the mark scheme and gave answers in terms of frequencies above 20 000 Hz. A few candidates spoilt their answers by referring to increased frequency and reduced or small amplitude. Where a candidate gives two answers, one right and one wrong, the examiner cannot pick which answer to mark and marks are not awarded.

 

 

E6.          Foundation Tier

          In part (a) the majority of candidates incorrectly gave ‘air’ and then ‘glass’. Many erroneous explanations were given in terms of ‘sound particles’ travelling easily through a gas. Part (b) was generally answered well, although a significant number of candidates could not recall the term ‘ultrasound’. In part (c) few of the responses were correct for both pulse size and position.

Higher Tier

          In part (a) a significant number of candidates incorrectly gave ‘air’ and then ‘glass’. Many gave an erroneous explanation in terms of ‘sound particles’ travelling easily through a gas. Those candidates correctly giving ‘glass’ then ‘air’ usually gave a correct reason for their choice. Part (b) was generally answered well, although a significant number of candidates could not recall the term ‘ultrasound’. In part (c) only the most able candidates saw the significance of both amplitude and position. Many candidates also included the reflected pulse from the original graph which was unnecessary and, unless clearly labelled, often spoilt their answer.

 

 

E7.          Foundation Tier

          Large numbers of candidates were able to demonstrate a working knowledge of the ray diagram for an optical fibre and many understood the reasons for thin fibre bundles being employed. Many correct applications were given in part (a)(iii) but rather too many employed a similar medical application to that already given. In part (b) candidates generally described the diagram, rather than mentioning ‘longitudinal’. Many answers to part (c) suggested ‘more particles’ but fewer inferred particle concentration. In part (d) many candidates identified that the bat listened to sounds, but many answers implied that the objects in its path produced signals rather than the bat itself. Few candidates understood that both the emission and detection of ultrasound involved the bat.

Higher Tier

          Most candidates were able to demonstrate a working knowledge of the ray diagram for an optical fibre and understood the reasons for thin fibre bundles being employed. Many correct applications were given in part (a)(iii) but rather too many employed a similar medical application to that already given. In part (b) candidates generally described the diagram, rather than mentioning ‘longitudinal’. Many answers to part (c) suggested ‘more particles’ but fewer inferred particle concentration or proximity of particles. In part (d) many candidates identified that the bat

listened to sounds, but many answers implied that the objects in its path produced signals rather than the bat itself. Few candidates understood that both the emission and detection of ultrasound involved the bat.

 

 

E8.          Foundation Tier

          Part (a) was poorly answered with very few candidates being able to give a reasonable definition of ultrasound. In part (b) most candidates thought that a wider beam would cause problems for both the mother and baby. Few considered that a narrow beam would give more detail. Most candidates were able to give sensible answers in part (b)(iv).

Higher tier

          Part (a) was answered poorly with very few candidates being able to give a reasonable definition of ultrasound. In part (b) most candidates thought that a wider beam would cause problems for both the mother and baby. Few considered that a narrow beam would give more detail. Most candidates were able to give sensible answers in both part (b)(iii) and part (b)(iv).

 

 

E9.          In part (a) few candidates were able to score full marks. The majority of candidates showed a poor understanding of amplitude, frequency and wavelength. Many answers contained contradictions, such as ‘frequency increases and pitch decreases’. Part (b)(i) was disappointing with many candidates unable to remember the word ultrasound or ultrasonic. The equation in part (b)(ii) was often correct but the subsequent calculation in part (b)(iii) was rarely correct, a common error being to leave the frequency in kHz.

 

 

E10.          The majority of candidates realised that the ultrasonic waves were reflected from the unborn baby, although a number of candidates used the unacceptable term ‘bounce back’. Very few candidates mentioned the time taken for the reflected wave to return as being used to produce the image. In part (b)(ii) most uses given were correct, but the answer ‘industrial cleaning’ was too vague to gain credit. A few candidates gave uses of gamma rays.

  

E11.          (a)     Most candidates secured both marks by writing that ultrasound has a frequency greater than 20 000 Hz and so cannot be heard by humans. However, some candidates offered responses which are true for sound in general, ‘It’s not as fast as light’ for example, and did not gain any credit.

(b)     (i)      Most candidates realised that the pulses are caused by ultrasound being reflected, though some candidates did not secure the mark because they offered ‘rebounded’ or ‘bounced’. Most candidates thought that pulse A indicates the crack and pulse B indicates the back of the block, or the back of the crack. Either interpretation gained credit provided that both pulses were identified.

(ii)     Most candidates correctly offered an answer in the range 88 – 92 (mm).

 

 

E12.          (a)     (i)      Most candidates identified the diagrams which showed traces with the same amplitude.

(ii)     Two thirds of candidates identified the two diagrams showing traces with the samefrequency.

(b)     (i)      Just over half of the candidates chose the correct range that a human child can hear.

(ii)     Just over half of the candidates gained a mark but those that did not often failed to mention that the frequency of the whistle was above 20 000 Hz. It was not sufficient to state that dogs can hear higher frequencies than humans.

(c)     (i)      Approximately a third of candidates gained both marks whilst three quarters of candidates gained at least one mark.

(ii)     Nearly two thirds of candidates identified that the information is collected by the ultrasound detector and gained a mark.

 

 

E13.          (a)     (i)      The majority of candidates scored a mark.

(ii)     Most candidates were able to explain that the diagrams represent different musical instruments because there are differences in detail between their shapes.

(b)     (i)      Most candidates knew the numerical value of the required frequency but some of them lost the mark because of careless use of units as illustrated by ‘20 000 kHz’.

(ii)     In part (b)(ii) most candidates understood the meaning of the word ‘media’ in the context of the short passage on ultrasound.

(iii)     Most candidates were able to obtain one mark out of the two for stating that some of the ultrasound is absorbed.

 

 

E14.          Foundation Tier

(a)(b) The majority of candidates chose the correct response and nearly all knew that the symbol kHz stands for kilohertz.

(c)     (i)(ii)  A significant minority of candidates could give an industrial use for ultrasound and a majority could give a medical use. It should be noted that vague responses such as ‘scanning organs’ did not gain a mark.Candidates needed to be more precise eg ‘scanning the kidneys’ or ‘scanning an unborn baby’.

(d)     Many candidates were able to interpret the diagram, and the information given about the scale, and correctly deduce that the time interval is 8 microseconds.

(e)     Few candidates were able to deduce that if the time interval is known then the distance travelled can be calculated.

(f)      Most candidates obtained a mark for the suggestion that, in this imaginary event, we should stop using ultrasonic waves but few had any sensible qualification to make and seemed unaware to the harm this reaction could cause.

          Higher Tier

(a)     Most candidates answered this correctly.

(b)     Nearly all candidates gained the mark for this question.

(c)     (i)(ii)  Most candidates could give an industrial use and a medical use for ultrasound. It should be noted that vague answers such as ‘scanning organs’ or ‘scanning babies’did not gain credit.Candidates needed to be more precise eg ‘scanning the kidneys’ or ‘scanning an unborn baby’.

(d)     Most candidates were able to interpret the diagram, and the information given about the scale, and correctly deduce that the time interval is 8 microseconds.

(e)     Over half the candidates gained one mark by deducing that if the time interval is known then the distance can be calculated but few of these candidates were able to state what the distance is in this case.

(f)      Nearly all candidates obtained a mark for the suggestion that, in this event, we should stop using ultrasonic waves and about half of these candidates had a sensible qualification to make such as the need for further research.

 

 

E15.          (a)     Many candidates gained 1 mark, but not the second, because they failed to mention that an ultrasound wave is a sound wave.

(b)     Some candidates did not make it clear that the cleaning fluid vibrates but successfully linked the ultrasound to removal of dirt.

(c)     Some well-reasoned responses were offered. However, a common error was to make an unfocussed point such as ‘humans are not mice’ or to make a valid initial point and then not follow it up.

 

 

E16.          (a)     This was well answered with nearly all candidates giving the correct answer.

(b)     (i)      Only a quarter of candidates correctly showed the amplitude. Over a third of candidates made no mark on the diagram at all.

(ii)     Under half of candidates knew that increasing amplitude increased volume/loudness. Most of the incorrect answers suggested frequency or pitch would change.

(c)     Over four fifths of candidates were able to obtain the correct answer from the graph.

(d)     Pleasingly, over three quarters of candidates were able to write a correct conclusion based on the graph. Many of those who did not do so either described how they got their answer to part (c) or just stated the co-ordinates of a point on the graph.

(e)     It was disappointing that only two fifths of candidates could give correctly both ends of the range of frequency for human hearing. More than a third of candidates gave totally incorrect values despite this being the third consecutive paper where it has been required.

 

 

E17.          (a)     This was well answered with over half of candidates gaining both marks and under a tenth of candidates not achieving any.

(b)     Many of the quarter of candidates who did not gain this mark either gave a vague answer such as‘scans’ or wrote an incorrect answer such as ‘X-rays’.

(c)     (i)      Surprisingly, just over a quarter of candidates were unable to count the number of waves and give the correct answer.

(ii)     Over four fifths of candidates were able to identify the pattern showing the most waves as being the one showing the highest frequency.

 

 

E18.          (a)     Many candidates lost marks by not being careful enough in taking readings from the

graph. A significant number of candidates gave 10 300 instead of 10 600.

(b)     Candidates had greater success in answering this part question. A common error however was to misread the scale and give an answer of 2500.

(c)     A considerable number of candidates misread the question as ‘Can most people hear the full range of sound the loudspeaker produces?’. The answers given suggested some confusion between loudness and frequency and many answers were very vague such that no marks could be awarded.

(d)     The majority of candidates understood that this procedure improves the reliability.

(e)     Most candidates only answered in terms of making it a ‘fair test’ which was insufficient.

 

 

E19.         (a)      (i)      A disappointing response to this part question with only just over 64% of candidates being able to count the number of waves shown correctly.

(ii)     With the benefit of ‘error carried forward’ just over 80% of candidates were able to score this mark.

(iii)     This was generally well answered with only a small proportion of candidates (9%) failing to score any marks. Most candidates knew the range of human hearing.

(b)     (i)      many candidates failed to score marks because correct terminology was not used: instead of reflection, words used included ‘detected’, ‘repulsed’, ‘bounced back’, ‘echoed’ and ‘transmitted’. There was some confusion between reflection and refraction. Misconceptions included that both pulses A and B resulted from cracks and that from A to B was the extent of the crack.

(ii)     Very few candidates (4%) scored all three marks. However many candidates scored some marks by showing a correct method using an incorrect distance. Others gained a mark for showing a method but forgetting to include the reflected distance. There was some confusion over the appropriate unit to give the numerical answer.

 

 

E20.         (a)      (i)      Just over 72% of candidates recognised which two traces had the same amplitude.

(ii)     Nearly 83% of candidates knew which trace represented the loudest sound.

(iii)     A large number of candidates incorrectly indentified the ultrasound as trace M with the reason ‘because it can’t be heard’. Of the 53% of candidates who correctly identified trace L many went on to describe characteristics of ultrasound rather than

relating their answer to the traces shown in the question and therefore failed to gain the second mark.

(b)     This question was well answered with 69% of candidates gaining both marks. Only 8.5% of candidates failed to score at least one mark.

 

 

E21.(a)     Students were asked to explain what ultrasound is but most only described what it can be used for. Therefore nearly three quarters of students gained no marks at all and only a small number gave enough information for both marks.

(b)     The majority of students achieved at least one mark.

(c)     The majority of students achieved at least one mark.

E22.(a)     Very few candidates obtained level 3 (5 or 6 marks), about half obtained level 1 (1 or 2 marks). In general, the responses regarding X-rays were answered in more detail than ultrasound. Many candidates were able to describe what the wave did, but failed to give accurate or detailed descriptions of the waves. Wavelength and frequency descriptions were often muddled. In many wrong responses, candidates failed to answer the question posed, often just appearing to write down any facts they had learned.

(b)     Almost half of the candidates failed to gain any mark on this question. Often wrong responses detailed how X-rays affected the human body, organs or tissues; rather than damage at a cellular level.

(c)     Less than one third of candidates could give a medical treatment using ultrasound. The most common correct response related to the treatment or removal of kidney stones. Many candidates with incorrect responses failed to note that the question asked for ‘other than imaging’ and stated scans of a fetus as their answer.

E23.(a)     (i)      Three-quarters of the students knew the frequency range of human hearing.

(ii)     Three-quarters of students knew what ultrasound is.

(iii)    Nearly all students could state a medical use of ultrasound. Most referred to viewing a fetus but other statements such as ‘pregnancy testing’ and ‘looking at babies’ did not score the mark.

(b)     The calculation which involved rearranging the wave equation and using data given in standard form was very well answered by the vast majority of students.

(c)     Ultrasound waves were emitted and the reflected waves from an object, moving away, were detected. Less than one-fifth of the students could correctly describe the differences between the emitted and reflected waves because it was often not clear which wave was being referred to in the answers.