Name: P6 WAVESSmall sailing boats can be fitted with a passive radar device. The device increases...

P6 WAVESPractice Questions

Name: ________________________

Class: ________________________

Date: ________________________

Time: 63 minutes

Marks: 63 marks

Comments: GCSE PHYSICS ONLY

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(a) Light waves transfer energy.

(i) Complete the following sentence.

The oscillations producing a light wave are ____________________________

to the direction of the energy transfer by the light wave.

(1)

1

(ii) The apparatus in the diagram shows that light waves transfer energy.

Describe how switching the desk lamp on and off shows that light waves transferenergy.

You do not need to describe the energy transfers.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

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(b) A student holds a wrist watch in front of a plane mirror. The student can see an image ofthe wrist watch in the mirror.

The diagram shows the position of the wrist watch and the mirror.

Draw a ray diagram showing how the image of the wrist watch is formed.

Mark the position of the image.

(4)

(c) The image of the wrist watch seen by the student is virtual.

What is a virtual image?

___________________________________________________________________

___________________________________________________________________

(1)

(Total 8 marks)

Diagram 1 shows a longitudinal wave being produced in a stretched spring.

2

(a) A longitudinal wave has areas of compression and areas of rarefaction.

Mark with the letter C, one area of compression shown in Diagram 1.

(1)

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(b) Diagram 2 shows the apparatus a teacher uses to demonstrate that sound can bereflected.

(i) Using a ruler, draw on Diagram 2 to show how sound from the loudspeaker isreflected by the sheet of metal to the sound sensor.

(2)

(ii) The teacher replaced the sheet of metal with a sheet of glass.

When he did this, the reading on the sound level meter went down.

Suggest why.

______________________________________________________________

______________________________________________________________

(1)

(iii) The teacher changed the output from the loudspeaker to increase the amplitude ofthe sound wave produced.

What effect, if any, does this increase of amplitude have on the loudness of thesound?

Draw a ring around the correct answer.

makes the soundquieter

does not change theloudness of the sound

makes the soundlouder

(1)

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(iv) The loudspeaker produces a sound wave at a frequency of 850 Hz. The wavelengthof the sound wave is 0.4 m.

Calculate the speed of the sound wave.

Show clearly how you work out your answer.

______________________________________________________________

______________________________________________________________

______________________________________________________________

Speed = ___________________________________ m/s

(2)

(c) Music concerts are sometimes performed in sports halls. The concerts can be spoiltbecause of the sound reflected from the floor and walls.

What word is used to describe a reflected sound?

___________________________________________________________________

(1)

(d) The graph shows how the percentage of sound reflected from the floor and from the wallsof a large room can be reduced by carpets and by curtains.

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(i) Over which range of frequencies do curtains reduce the percentage of soundreflected the most?

Tick ( ) two boxes.

from 250 Hz to 750 Hz



(1)

(ii) The manager of a sports hall plans to use the hall for regular music concerts. He hasenough money to buy either carpet or curtains, but not both.

To improve the sound an audience hears, it would be better to hang curtains on thewalls rather than laying a carpet over the floor.

Use the data in the graph to explain why.

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(2)

(Total 11 marks)

(a) Radio waves, microwaves and visible light are all electromagnetic waves that are used forcommunication.

(i) Name another electromagnetic wave that is used for communication.

______________________________________________________________

(1)

3

(ii) Name an electromagnetic wave which is not used for communication.

State a use for this electromagnetic wave.

Electromagnetic wave ___________________________________________

Use __________________________________________________________

______________________________________________________________

(2)

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(b) The table below shows the wavelengths for some electromagnetic waves, A, B, C and D.

Wave Wavelength

A 1000 m

B 100 m

C 10 m

D 3 cm

A teacher is going to demonstrate diffraction of waves through a gap. She will carry out thedemonstration in a classroom.

The teacher is able to generate waves A, B, C and D.

Which wave, A, B, C or D, would she use?

Explain your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

(3)

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(c) In another demonstration, a teacher used a loud ticking clock as a source of sound, twohollow tubes and two smooth surfaces, EF and GH.

The figure below shows one of the hollow tubes fixed in position with a ticking clock at oneend.

A student placed his ear at one end of the other hollow tube in position P. He moved thishollow tube, in turn, to positions Q and R.

(i) At which position, P, Q or R, did he hear the loudest sound?

(1)

(ii) Explain your answer to part (i).

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______________________________________________________________

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(3)

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(iii) Suggest why smooth surface GH in the figure above was needed.

______________________________________________________________

______________________________________________________________

(1)

(iv) The frequency of a sound wave is 15 Hz.

The speed of sound is 330 m / s.

Calculate the wavelength of the sound wave.

______________________________________________________________

______________________________________________________________

Wavelength = ______________________ m

(2)

(v) Give a reason why it would not be possible to do the demonstration in the figureabove using sound waves with a frequency of 15 Hz.

______________________________________________________________

______________________________________________________________

(1)

(Total 14 marks)

Small sailing boats can be fitted with a passive radar device. The device increases the chancethat the small boat will be seen on the radar screen of a large ship.The radar transmitter on the large ship emits microwaves.

(a) Microwaves and radio waves are both part of the electromagnetic spectrum.

How are microwaves different from radio waves?

___________________________________________________________________

___________________________________________________________________

(1)

4

(b) How fast do microwaves travel through the air or a vacuum compared to radio waves?

___________________________________________________________________

(1)

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(c) The diagrams show the position of a passive radar device on a small boat and the internalconstruction of one type of passive radar device.

Microwaves can be absorbed, reflected or transmitted by different materials and types ofsurface.

Explain what happens to the microwaves from the ship’s transmitter when they reach thepassive radar device.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

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(2)

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(d) Each type of passive radar device has an RCS value. The larger the RCS value, the easierit is for a small boat fitted with the device to be detected.

An independent group of scientists measured the RCS values of 4 different types of device.The RCS value for each device was measured in the same room using the sameequipment.

(i) Why are the walls of the room covered in a material that absorbs the waves emittedby the radar transmitter?

______________________________________________________________

______________________________________________________________

(1)

(ii) Why is it important to use the same room and the same equipment?

______________________________________________________________

______________________________________________________________

(1)

(iii) Why is it important that the measurements are made by an independent group ofscientists?

______________________________________________________________

______________________________________________________________

(1)

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(e) The movement of a small boat causes the mast and device to lean over, therefore the RCSvalues were measured at different angles.

The table gives the RCS values obtained by the scientists.

Device

Angle X

0 ° 5 ° 10 ° 15 °

A 1.4 1.6 1.7 1.8

B 4.7 2.6 2.3 1.9

C 9.3 3.3 1.9 1.1

D 4.5 4.8 5.0 4.6

(i) Describe how the RCS values for device A are different to the RCS values for deviceB.

______________________________________________________________

______________________________________________________________

______________________________________________________________

______________________________________________________________

(2)

(ii) The scientists recommended that a passive radar device fitted to a small boat shouldhave:

• the largest possible RCS value

• an RCS value consistently above 2.0

Which one of the devices, A, B, C or D, would you recommend that someone fits totheir boat?

_______________________

Give a reason for your answer.

______________________________________________________________

______________________________________________________________

(1)

(Total 10 marks)

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The drawing shows someone ironing a shirt. The top of the ironing board is covered in a shinysilver-coloured material.

5

Explain why the shiny silver-coloured material helps to make ironing easier.

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(Total 2 marks)

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The diagram shows a model used to demonstrate an illusion known as ‘Pepper’s Ghost’.

A small light bulb and thin sheet of glass are put inside a box. The thin sheet of glass acts as amirror. Although the light bulb is switched on, a student looking into the box cannot see the bulb.What the student does see is a virtual image of the bulb.

(a) Use a ruler to complete a ray diagram to show how the image of the light bulb is formed.Mark and label the position of the image.

(4)

6

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(b) The image seen by the student is virtual.

Why?

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(1)

(Total 5 marks)

The diagram shows a glass prism.

7

(i) Explain why refraction has not occurred at point X.

___________________________________________________________________

___________________________________________________________________

(1)

(ii) (A) Give the full name for the process which has occurred at point Y.

______________________________________________________________

(1)

(B) Explain why this process has occurred.

______________________________________________________________

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(2)

(Total 4 marks)

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The diagram shows the apparatus that a student used to investigate the heating effect of differentwavelengths of light.

8

(a) (i) The student put thermometer D outside of the light spectrum.

Suggest why.

______________________________________________________________

______________________________________________________________

(1)

(ii) The table gives the position and reading of each thermometer 10 minutes after theinvestigation started.

Thermometer Position of thermometer Temperature in °C

A in violet light 21

B in green light 22

C in red light 24

D outside the spectrum 20

What should the student conclude from the data in the table?

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(2)

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(b) A similar investigation completed in 1800 by the scientist Sir William Herschel led to thediscovery of infrared radiation.

Suggest how the student could show that the spectrum produced by the glass prism has aninfrared region.

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(2)

(c) A person emits infrared radiation at a frequency of 3.2 x 1013 Hz.

Calculate the wavelength of the infrared radiation that a person emits.

Take the speed of infrared radiation to be 3.0 x 108 m/s.

Show clearly how you work out your answer.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Wavelength = _________________________ m

(2)

(d) A thermal imaging camera detects infrared radiation. Electronic circuits inside the cameraproduce a visible image of the object emitting the infrared radiation.

At night, police officers use thermal imaging cameras to track criminals running away fromcrime scenes.

Thermal imaging cameras work better at night than during the day.

Explain why.

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(2)

(Total 9 marks)

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Mark schemes

(a) (i) perpendicular

accept correct description 11

1

(ii) light off – no / slow rotation1

light on – fast(er) rotation

accept starts rotating

ignore references to energy transfers1

(b) one ray drawn from wrist watch and reflected by mirror

accept solid or dashed lines1

two rays drawn from wrist watch and reflected by mirror with i = r for both rays

judge angles by eye1

one ray traced back behind mirror

accept solid or dashed lines1

image in correct position

judged by eye

accept image marked where two reflected rays traced back crossbehind the mirror

1

(c) cannot be formed on a screen

accept image formed behind the mirror

or

rays of light seem to come from it but do not pass through it1

[8]

(a) letter C clearly marking a compression

accept C at any point in a compression

if more than one letter C markedall must be correct

1

2

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(b) (i) straight continuous line drawn from loudspeaker to metal to sound sensor

judge by eye1

angle I = angle R

judge by eye

ignore any arrows on lines1

(ii) less sound reflected

accept energy for sound

or

(some) sound passes through the glass

accept (some) sound absorbed by the glass1

(iii) makes the sound louder1

(iv) v = f × λ

340

allow 1 mark for correct substitutionie 850 × 0.4

provided no subsequent step shown2

(c) echo1

(d) (i) from 250 Hz to 750 Hz1

(ii) curtains reduce (percentage of) sound reflected more (than carpet)

accept curtains absorb more sound (than carpet)1

for all frequencies (shown)

accept for both marks an answer in terms of walls having a larger(surface) area to reflect sound and curtains reducing the amount ofreflected sound more (than carpet)

answers less noisy or walls / curtains have a larger area gain 1mark only

do not accept curtains are cheaper1

[11]

(a) (i) infrared / IR13

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(ii) UV / X-rays / gamma rays1

appropriate use corresponding with given wave:

dependent on first marking point

• UV: security marking or tanning• X-rays: medical imaging or checking baggage• gamma rays: sterilising surgical instruments or killing harmful bacteria in

food

accept any sensible alternative uses1

(b) D1

gap must be comparable to wavelength

accept converse1

can create gap of that size in classroom

dependent on first marking point1

(c) (i) Q1

(ii) sound waves reflected

accept ‘it’ for sound waves

ignore bounce1

at EF1

angle of incidence equal to angle of reflection1

(iii) stop sound going direct from clock to ear1

(iv) 22 (m)

allow 1 mark for correct substitution, ie

330 = 15 × λ scores 1 mark2

(v) outside audible range1

[14]

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(a) higher frequency

general properties / uses are neutralorshorter wavelength

do not accept different frequency / wavelength / energyorgreater energy

1

4

(b) the same (speed)

accept they travel at the speed of light1

(c) pass through / transmitted by the plastic / casing1

reflected by the metal / plates

do not accept bounce / deflected etc for reflected

if neither marking point scores an answer reflected (back to boat /from the device) scores 1 mark

1

(d) (i) waves are not reflected from the walls

accept microwaves / radar for waves

do not accept bounce / deflected etc for reflectedoronly waves (reflected) from the device are detected

accept to stop reflected waves affecting results1

(ii) different types (of device) can be compared

fair test is insufficient

accept idea that only one variable is then changed1

(iii) so (measurements / results / scientists) are not biased towards one type /manufacturer of device/s

accept to avoid bias

accept so they are not biased1

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(e) (i) any two from:

if temperature is mentioned rather than angle a maximum of 1 markcan be scored

• (for any angle) A values < B values

or converse eg B values are higher / better / stronger

• A values increase with (increasing) angle

accept weakest at 0° strongest at 15°

values go up is insufficient

• B values decrease with (increasing) angle

accept strongest at 0° weakest at 15°

values go down is insufficient

• A values do not vary as much (as B values)2

(ii) D

mark is for the reason

reason cannot score if D is not chosen

values are always over 2(.0)1

[10]

silver is a (good) reflector of heat(radiation) orsilver reflects the heat (radiation)

factheat = infra redignore references to lightaccept shiny for silvergood radiator negates the mark

ignore references to good conductor

do not accept bounce back1

5

less heat is lost through the board or more heat is retained by the shirt

explanationaccept both sides of shirt heated

reflects heat back up gets 1 mark onlyignore mention of friction

1

[2]

(a) two rays drawn from the bulb and reflected by the glass

angle I = angle R judged by eye

allow 1 mark for one incident and reflected ray even if angle Idoesn’t equal angle R

2

6

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at least one arrow drawn in correct direction

any conflicting arrows negate this mark

ignore any arrows drawn on construction lines behind the glass1

position of image correct

judged by eye1

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(b) image is formed by virtual / imaginary rays crossing

accept construction lines only show where the light seemsto come from

accept the image is behind the glass / mirror

accept image is seen through the glass / mirror

accept (real) rays of light do not pass through the image

accept (real) rays do not cross

accept the image is a reflection (of the object)

accept the image is formed by reflection

do not accept a virtual image can’t be formed on a screen

do not accept the object / image is reflected1

[5]

(i) (incident) ray along the normal

or (incident) ray at 90 ° ( t o t he su r f ace )1

(ii) (A) total internal reflection

all three words required do not credit total internal refraction1

7

(B) EITHERangle of incidence is greater than the critical angle

or angle of incidence is greater than 42°2

ORangle of incidence is 45°

1

[4]

(a) (i) to check rise in temperature (of other thermometers) was due to the(different wavelengths of) light

accept as a control / comparison

to measure room temperature is insufficient1

8

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(ii) any two from three:

• different colours produce different heating effects / (rises in) temperatures

• red light produces the greatest heating effect / (rise in) temperature

or

• violet produces the least heating effect / (rise in) temperature

• all colours produce a greater heating effect than outside the spectrum

an answer

the longer the wavelength the greater the (rise in) temperature

or

the lower the frequency the greater the (rise in) temperature gainsboth marks

2

(b) move a thermometer into the infrared region / just beyond the red light

allow use an infrared camera / infrared sensor1

the temperature increases beyond 24(°C)

accept temperature higher than for the red light1

(c) v = f × λ

9.4 × 10-6

accept 9.375 × 10-6 or 9.38 × 10-6

or

0.0000094

accept 0.000009375

or 0.00000938

allow 1 mark for correct substitution

ie 3 × 108 = 3.2 × 1013 × λ2

(d) at night the surroundings are cooler

accept at night the air is colder

there is no heat from the Sun is insufficient

or

at night there is a greater temperature difference between people andsurroundings

1

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(so surroundings) emit less infrared (than in daytime)

accept camera detects a greater contrast

or

gives larger difference in infrared emitted (between people and surroundings)1

[9]

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Name: P6 WAVESSmall sailing boats can be fitted with a passive radar device. The device increases...

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