Edexcel IGCSE Section 3 Waves

Section 3 Waves

2005 june

Q3: The diagram represents the electromagnetic spectrum.

Gamma-rays X-rays Ultraviolet Visible Infra-red Microwaves Radio waves

(a) Which of X-rays and radio waves has the longer wavelength? ......................................................................................................................................(1) (b) Which of X-rays and radio waves has the higher frequency? ......................................................................................................................................(1) (c) State one use of X-rays. ......................................................................................................................................(1) (d) State one property that all electromagnetic waves have in common. ......................................................................................................................................(1) (e) State the law of reflection. ...................................................................................................................................... (1) (f) A teacher wants to demonstrate the law of reflection to his class. Suggest two reasons why he should use visible light rather than X-rays. 1 ................................................................................................................................... 2 ...................................................................................................................................(2)

(Total 7 marks)

Khalid Mazhar Qureshi www.edexcel-cie.com

Answer


Q7: The diagram shows an example of an analogue signal and an example of a digital signal.

Complete the sentences. (a) The analogue signal varies ............................................ between a maximum and minimum value. (1) (b) The digital signal only has two values. These are 1 which corresponds to ......................... and ......................... which corresponds to .......................... (3) (Total 4 marks)


Answer


Q12 (a) Astudent uses a rectangular glass block to determine the refractive index of the glass.

(i) Describe the experiment. Draw a diagram to illustrate your answer.

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................(4) (ii) The student finds that when the angle of incidence in the air is 68 the angle of refraction in the glass is 38. The table contains information about the two angles.

Angle Cosine Sine Tangent

380 .79 .62 .78

680 .37 .93 2.48

Calculate the refractive index of the glass. ............................................................................................................................... ............................................................................................................................... ................................................... Refractive index = .............................. (3) (b) (i) What does the term critical angle mean? ............................................................................................................................... ............................................................................................................................... (2) (ii) State the relationship between the critical angle and the refractive index. ............................................................................................................................... ............................................................................................................................... (1) (Total 10 marks)


Answer


2005 Nov

Q1: (a) Are sound waves in air transverse or longitudinal? ......................................................................................................................................(1) (b) A sound wave has a frequency of 384 Hz and a wavelength of 0.86 m. Calculate its speed in m/s. ...................................................................................................................................... ...................................................................................................................................... Speed = ....................................................... m/s (2) (c) Another sound wave has a frequency of 38 400 Hz. (i) Would you be able to hear this sound wave? ............................................................................................................................... (1) (ii) Explain your answer. ............................................................................................................................... (1)

(Total 5 marks)


Answer

(a) longitudinal 1 (b) use and recall v = f x

384 x 0.86 = 330 (m/s) 1 1

(c) (i)

no 1

(c) (ii)

not within (audible) range of 20 20 000 Hz

frequency too high 1

Total 5 marks


Q6: (a) Complete the sentence. When light is incident on a mirror the angle of incidence equals the angle of ............................................................ (1) (b) The diagram shows a kitten sitting in front of a mirror. A virtual image of the kitten is formed by the mirror.

The image of the end of the kittens tail is formed at C. One incident ray from the tail is shown. Draw its reflected ray and then construct further rays to show the image formation at C.

(3)

(Total 4 marks)


Answer

Question 6 (a) reflection

1

(b) draw reflected ray draw second ray from cat tail reflected in mirror drawn reflected rays converge at C

angles of incidence and reflection equal by eye ditto

1 1 1

Total 4 marks


Q10: (a) A student sings into a microphone.

Complete the sentence. The useful energy transfer made by the microphone is from sound energy to .............................. energy. (1) (b) The amplitude, the frequency and the wavelength of a sound wave can be changed. (i) What change could be made to make the sound lower in pitch? ............................................................................................................................... (1) (ii) What change could be made to make the sound louder? ............................................................................................................................... (1) (c) A sound wave, wavelength , approaches a gap in a wall. (i) Name the effect which occurs as the sound wave passes through the gap. ............................................................................................................................... (1) (ii) Complete the sentence. The greatest effect occurs when ................................................. is equal to (1) (d) Describe how you could measure the speed of sound in air by a simple direct method. You may draw a diagram to illustrate your answer. ...................................................................................................................................... ...................................................................................................................................... ...................................................................................................................................... ......................................................................................................................................(4) (Total 9 marks)


Answer

Question 10 (a) electrical allow electricity 1 (b)(i) reduce frequency allow lower/drop

frequency or increase wavelength

1

(b)(ii) increase amplitude allow raise amplitude 1 (c) (i)

diffraction allow diffracted 1

(c) (ii)

(the width of the) gap 1

(d) measure distance (1) start to measure time when sound generated (1) one correct mention of appropriate measuring instrument i.e. metre rule/tape, stop watch/clock and no inappropriate mention (1) indication that speed = distance time (1)

if echo method must be clear that this is the distance there and back if observer method must be clear how observer knows the moment sound generated points may be credited either from written response or from diagram but do not credit the point if writing and diagram contradict

4

Total 9 marks


2007 june

Q3: (a) State the law of reflection.

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

(b) A student is playing in goal in a football match. The window of a nearby building

reflects sunlight into his eyes.

(i) Complete the diagram to show the reflection of the ray from the front of the

window. (2)

(ii) What could you do to stop sunlight being reflected into the students eyes from this window?

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

(c) Light is part of the electromagnetic spectrum. If players are not protected from

some electromagnetic waves they can suffer ill effects. State which part of the

electromagnetic spectrum can cause

(i) skin burns

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

(ii) blindness.

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

(d) What do all parts of the electromagnetic spectrum have in common?

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

(Total 7 marks)


Answer

Question Answer Extra Info. Marks

3a angle of incidence equals

angle of reflection

(angle) i = (angle) r

Q6: (a) The diagram shows what happens when water waves pass close to the edge of a piece

of plastic.

Name the wave behaviour shown.

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

(b) The diagram below shows water waves about to pass through a gap.

One wavefront is shown after it has passed through the gap.

(i) On the diagram, draw two more wavefronts that have passed through the gap. (3)

(ii) State two changes which would each make the wavefronts become more curved

after passing through the gap.

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

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

(c) (i) Sound waves with a frequency of 25 000 Hz are directed at a gap. Give a reason

why they are not heard on the other side of the gap.

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


(ii) Calculate the wavelength in metres of these sound waves.

The speed of sound is 340 m/s.

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

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

Wavelength = .................................m (3)

(Total 10 marks)


Answer

Q# 6 Answer Extra Info. Marks

a diffraction accept phonetic spelling 1

b(i) correct shape

same wavelength

two more wavefronts

1

1

1

b(ii) increase wavelength

decrease size of gap

or decrease frequency

ignore speed

do not credit make equal

1

1

c(i) outside audible range frequency too high

or it/25 000 (Hz) is

ultrasound

or range of (human) hearing

is 20 to 20 000 (Hz)

ignore reference to gap

1

c(ii) v = f = 340 / 25 000 = 0.0136 (m)

recall in any form

manipulation and substitution

or 0.014 (m)

1

1

1


Q7: A teacher draws a diagram on the board showing an analogue signal and a digital signal.

............................. signal ............................. signal

(a) (i) Complete the labels to show which is the analogue signal and which is the digital

signal. (1)

(ii) Give two reasons for your answer.

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

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

(b) State one advantage of using digital signals rather than analogue signals.

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

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

(c) Give one example from everyday life of the use of a digital signal.

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

(Total 5 marks)


Answer


a-i left : analogue

right : digital

1

a-ii analogue continuous digital on and off

allow continual / has any

value / values /

has many values

1 or 0 / only two values or

allow two reasons for either

analogue or digital

1

1

B one advantage clearer/less prone to

interference

can be reproduced / repaired /

restored

do not credit just can be amplified zero interference

1

C telecommunications allow any feasible response

e.g. CD players

1


Q9: Complete the sentences about sound waves.

(a) We cannot see a sound wave. However we can see a representation of it by connecting

a microphone to ............................................................................................................ (1)

(b) The pitch of a sound depends on ................................................................................. (1)

(c) The loudness of a sound depends on ............................................................................ (1)

(Total 3 marks)


Answer


A (a cathode ray) oscilloscope/ CRO 1

B (the) frequency (of vibration/the wave) (number of) cycles per second 1

C amplitude (of vibration/the wave) accept its energy / intensity not volume

1


Q14: (a) The diagram shows a ray of light directed at a semicircular glass block.

(i) Name line X.

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

(ii) Which angle a, b, c, d, e or f is an angle of incidence?

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

(iii) Name angle b.

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

(iv) State an equation which relates angle of incidence, angle of refraction and

refractive index of glass.

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

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

(v) At point Y light passes from air to glass but refraction does not take place.

How can you tell this from the diagram?

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

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

(vi) Why does refraction not take place at point Y.

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

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


(b) Glass with a critical angle of 42 was used to make the blocks shown below.

(i) Complete the diagram to show how the ray of light passes through the rectangular

glass block and out into the air.

(ii) Complete the diagram to show how the ray of light passes through the triangular

glass block and out into the air.

(2)

(Total 11 marks)


Answer


a-i normal do not accept perpendicular or vertical

1

a-ii (angle) e / E accept phonetic spelling but not anything which could be taken for

refelction

1

a-iii (angle of) refraction n = sin i/ sin r 1

a-iv refractive index = sine of angle of incidence sine of angle of refraction

allow its a straight line 1

a-v continues in the same direction / does not bend

1

a-vi any one of

ray is on the normal angle of incidence = 0 angle of refraction = 0 at 90 / right angles to the boundary / perpendicular

1

b-i refraction towards normal (1) then refraction away from normal

at the opposite face (1)

emergent ray appears to be parallel to

incident ray (1)

2

b-ii ray continues in a straight line to back force (1)

reflects down and straight out at right

angles

dop 3


2007 Nov

Q3: (a) (i) Define frequency.

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

(ii) Define time period.

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

(b) A student has a heart rate of 72 beats per minute.

Calculate

(i) the frequency of his heart beat in hertz

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

(ii) the time period of his heart beat in seconds.

Time period = ................................. s (1)

(c) Generally the heavier an animal is, the lower is its heart rate. The data in the table

gives the heart rate of animals of different masses.

Mass (kg) 100 200 300 400 500 600

Heart rate

(beats per

minute)

63 53 48 45 42 40

(i) Use the grid opposite to plot a graph of heart rate against mass. Draw a smooth

curve for your plotted points. (3)


(ii) This animal has a mass of 5000 kg.

Explain why you cannot use your graph to predict the heart rate of this animal.

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

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

(Total 8 marks)


Q10: A teacher uses a microphone and another piece of equipment to display a sound wave.

(a) Name the other piece of equipment.

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

(b) The teacher measures distance d on the screen. Complete the sentences.

(i) Distance d represents ............................................................................................. (1)

(ii) Distance d becomes smaller. This is because the sound which goes to the

microphone has become ........................................................................................ (1)

(c) Complete the sentence.

The pitch of the sound depends on ...............................................................................

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

(Total 4 marks)


Q14: (a) State one use for optical fibres.

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

(b) The diagram shows a ray of light moving through part of an optical fibre.

(i) Add the normal and the angle of incidence to the diagram.

(2)

(ii) Name the process which takes place in the diagram.

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

(iii) Use the term critical angle to explain why the process takes place.

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

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

(c) (i) State the equation which relates critical angle and refractive index.

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

(ii) The critical angle for glass in an optical fibre is 41.5.

cos 41.5 = 0.749

sin 41.5 = 0.663

tan 41.5 = 0.885

Calculate the refractive index of glass to three significant figures.

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

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

Refractive index = ............................ (3)


(d) A bicycle reflector is made of transparent red plastic. The diagram shows the path of

a ray of light through part of the reflector.

The critical angle for the transparent red plastic is less than 45. Explain how you can

tell this from the diagram.

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

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

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

...................................................................................................................................... (3)

(Total 12 marks)

2008 June

Q2: Parts of the electromagnetic spectrum have various uses.

(a) Which part is used for

(i) heaters and night vision equipment,

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

(ii) sterilising food and medical equipment?

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

(b) All the parts of the electromagnetic spectrum are transverse waves.

(i) State one property which all the parts have in common but which is not shared

with other waves.

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

(ii) Give one example of a transverse wave which is not part of the electromagnetic

spectrum.

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

(iii) Complete the sentence below.

In a transverse wave, each point on the wave is moving in a direction

which is ............................................................ to the direction in which

the ............................................................ of the wave is moving. (2)

(Total 6 marks)


Q10: A student used pins to trace a ray of light through a block of glass of refractive index 1.5.

She produced the diagram shown below.

It shows a ray of light being refracted with an angle of refraction of 40.

(a) Calculate the angle of incidence, in degrees, of the ray of light.

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

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

Angle of incidence = .............................. (3)

(b) The experiment is repeated with a block of water. The refractive index of water is 1.3. The same angle of incidence is used.

(i) On the diagram above draw the refracted ray for a block of water. (1) (ii) Explain the direction of the ray that you have drawn in (i).

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

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

(c) The diagram below shows a semicircular glass block. An incident ray is drawn.

Add one more line to the diagram and mark the angle of incidence, i, for this ray.

(2)

(Total 8 marks)


2008 November

Q2: The diagram shows a fisherman standing in water.

(a) In 8 seconds, 4 complete waves pass the fisherman.

Calculate the frequency of the waves and give the unit.

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

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

(b) These water waves are transverse waves.

Name one other example of a transverse wave.

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

(c) Complete the sentence.

Waves can transfer energy and ........................................................ without

transferring matter. (1)

(d) What is meant by the time period of a wave?

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

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

(2)

(Total 6 marks)


Q9: (a) A student shines a ray of light at a glass block as shown below. The refractive index

of the glass is 1.6.

Show on the diagram for this ray of light

(i) the angle of incidence from air to glass and label it I, (1)

(ii) the angle of refraction inside the glass and label it R, (1)

(iii) the critical angle and label it C. (1)

(b) (i) What does the term critical angle mean?

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

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

(ii) State the relationship between critical angle and refractive index.

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

(iii) Calculate the critical angle in degrees for this block of glass.

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

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

Critical angle = ....................................... (1)

(c) The diagram below shows the ray of light entering the glass block at point P. The

dashed path is for glass of refractive index 1.6.


(i) Draw the path of the ray from P if the refractive index of the glass is greater than

1.6. (2)

(ii) Explain the path that you have drawn.

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

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

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

(Total 10 marks)


2009 June

Q2: A student ties one end of a rope to a chair. She uses the rope to demonstrate wave

behaviour to her class.

(a) She produces a transverse wave as shown below. A is the direction of vibration and

B is the direction of the wave.

(i) State how the student could increase the amplitude of the wave.

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

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

(ii) State how the student could decrease the wavelength to produce the wave shown

below.

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

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


(b) When the frequency of the wave is 1.5 Hz, the wavelength is 0.80 m. Calculate the

speed in m/s of the wave.

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

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

Speed = ...................................... m/s (3)

(c) The student then uses a spring to demonstrate the behaviour of a longitudinal wave.

Draw arrows on this diagram to show

(i) the direction of vibration, and label this A.

(ii) the direction of the wave, and label this B. (2)

(Total 8 marks)


Q18: A small submarine explores the sea-bed. The submarine has a TV camera and a powerful

searchlight.

The diagram shows the path of light from the searchlight to the surface. The angle of

incidence at the surface is equal to the critical angle between sea-water and air.

(a) On the diagram, use a ruler to continue the path of most of this light. (1)

(b) State the meaning of the term critical angle.

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

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

(c) State the equation which relates critical angle and refractive index.

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

(d) (i) What happens to the light from the searchlight when it has an angle of incidence

at the surface which is greater than the critical angle?

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

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

(ii) State the full name of the process which occurs.

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


(e) Information from the TV camera is sent to a support ship by means of a cable of

optical fibres.

Use a ruler to complete the diagram below to show how information is transmitted

through an optical fibre.

(2)

(Total 7 marks)


2009 November

Q6: (a) Diagrams A, B and C show the behaviour of waves.

Use a word from the box to name each behaviour.

Diffraction Interference Refraction

Reflection Wavefront Wavelength

A ..................................................................................................................................

B . ..................................................................................................................................

C .................................................................................................................................. (3)

(b) Diagram C shows a reduction in the speed of the waves.

Explain how.

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

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


(c) The gap in A is made smaller, as shown below. Draw three waves after the gap.

(2)

(Total 7 marks)


Q14: (a) The diagram shows a ray of light passing through one side of a pair of binoculars.

(i) Name the parts labelled P and Q.

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

(ii) Name the process shown by the path of the light in parts P and Q.

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

(b) Figures A and B show rays of light from a lamp on the bottom of a swimming pool.


(i) Answer these three questions with reference to Figure A.

1. What is the name of the dashed line CD?

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

2. Use two of the letters u, v, w, x, y and z to write the equation angle of incidence = angle of reflection

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

3 State the equation which relates refractive index n, angle of incidence i and angle of refraction r.

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

(ii) Refraction has not occurred in Figure B. Explain this.

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

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

(iii) State the equation which relates critical angle c and refractive index n.

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

(Total 7 marks)


Q15: A radio station broadcasts at a frequency of 1200 kHz. The radio waves travel

outwards from the radio transmitter at a speed of 300 million metres per second

(300 000 000 m/s).

(a) (i) State the equation which relates frequency, speed and wavelength.

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

(ii) Calculate the wavelength of these radio waves.

Show your working and give the unit.

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

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

Wavelength = .......................................... (3)

(b) Use the equation

Frequency =

to calculate the time period in seconds of these radio waves.

Give the answer to two significant figures.

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

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

Time period = .........................................s (3)

(Total 7 marks)


2010 JUNE

Q3: The diagram shows a wave on the surface of the water of a swimming pool and a ball

floating on the water.

(a) Identify the features of the wave shown by:

(i) distance c;

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

(ii) distance d.

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

(b) A student observes the wave.

There are thirty complete cycles in one minute.

Calculate the frequency, in hertz, of the waves.

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

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

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

(c) (i) Identify the type of wave.

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

(ii) Describe the motion of the ball as the wave occurs.

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

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

(Total 6 marks)


Q10: The diagram shows a torch emitting a beam of light from two different positions A and B

under water.

(a) What is the name of the two dotted lines on the diagram?

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

(b) State the relationship between critical angle and refractive index.

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

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

(c) Explain the paths followed by the two beams of light.

Refer to the critical angle in your answers.

(i) Path from position A.

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

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

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

(ii) Path from position B.

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

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

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


(d) Explain why it is not possible to use the relationship in (b) to find the refractive index

of water using an angle from the diagram.

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

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

(e) (i) State the relationship between refractive index, angle of incidence and angle of

refraction.

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

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

(ii) Use angles from the diagram to calculate the refractive index of water.

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

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

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

Refractive index = ................................... (2)

(Total 10 marks)


2010 Nov

Q15: (a) The diagram shows a ray of light going through air towards a glass block with a

curved surface.

(i) Use a ruler to draw the path of the ray as it continues towards the glass block and

then goes through the glass block.

Add labels to the diagram to show the following:

incident ray normal angle of incidence, i refracted ray angle of refraction, r (4) (ii) Name two pieces of apparatus that would be required to carry out this

experiment.

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

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

(b) In an experiment a student gets the following results.

i r

Set 1 50 30

Set 2 5 3


(i) State the relationship between i, r and refractive index, n.

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

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

(ii) Calculate a value for refractive index using Set 1.

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

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

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

Refractive index = ..................................................... (2)

(iii) State why Set 2 gives a less reliable value.

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

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

(Total 10 marks)


Q16: The diagram shows a waveform on an oscilloscope screen.

(a) The timebase is set at 0.01s per division.

Determine the frequency of this wave and give its unit.

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

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

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

Frequency = .......................................... (3)

(b) A teacher demonstrated a method for determining the speed of sound.

He hit two metal rods together to produce a sound.

The sound was detected by two microphones connected to an oscilloscope.


The screen of the oscilloscope showed two signals A and B corresponding to the

sound received by the two microphones.

The time between the signals was 0.002 s and the distance between the microphones

was 0.680 m.

(i) Calculate the speed of sound in m/s.

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

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

Speed = ................................ m/s (2)

(ii) State which property of a sound wave is represented by the amplitude of the

signals.

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

(iii) Suggest an explanation for the relative sizes of the amplitudes of A and B.

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

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

(2)

(Total 8 marks)


Documents

Edexcel IGCSE Section 3 Waves