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WavesSeparate Physics
Waves facts
Name ______________________________
Class ______________________________
Teacher ______________________________
1) A wave transfers energy from one place to another.2) A vibration. 3) The vibration causing a transverse wave is
perpendicular to the direction of travel of the wave.4) The vibration causing a longitudinal wave is parallel
to the direction of travel of the wave. 5) Sound, ultrasound and primary earthquake (P) waves6) Water waves, all EM waves and secondary
earthquake (S) waves. 7) A compression is when particles in a longitudinal
wave are closest together. 8) A rarefaction is when particles in a longitudinal wave
are furthest apart. 9) The amplitude is the maximum displacement of a
wave from its equilibrium position. 10) The wavelength is the distance from a point on one
wave to the same point on the next wave. 11) The frequency is the number of waves passing a point
each second. 12) Wave speed – m/s, wavelength – m, frequency – Hz.
13) v = f × λ14) 300,000,000 m/s15) 330 m/s16) Radio, microwave, infra-red, visible, ultra-violet,
x-ray, gamma.17) Gamma18) Gamma19) Ultra-violet, x-ray and gamma. 20) It refracts towards the normal as glass is more dense
than air. 21) It refracts away from the normal as air is less dense
than glass. 22) The angle of incidence is equal to the angle of
reflection. 23) Can cause skin to age prematurely and increase the
risk of skin cancer. 24) X-rays and gamma rays are ionising radiation that can
cause the mutation of genes and cancer. 25) Television and radio transmission. 26) Satellite communication (as they can travel through
ionosphere) and for cooking food.27) Electrical heaters, cooking food and infrared cameras28) Fibre optic communications (and our vision!)29) Energy efficient lamps, sun tanning. 30) Medical imaging and security scanning. 31) Medical treatment (radiotherapy).
1) What does a wave transfer?2) What causes a wave?3) What is the definition of a transverse wave?4) What is the definition of a longitudinal
wave?5) Give three examples of longitudinal waves. 6) Give three examples of transverse waves7) What is a compression?8) What is a rarefaction?9) What is the amplitude?10) What is the wavelength?11) What is the frequency?12) What are the units of wave speed,
wavelength and frequency?13) What is the wave speed equation?14) What speed do EM waves travel at?15) What speed does sound travel at?16) List the EM waves in order from longest to
shortest wavelength. 17) Which EM wave has the highest frequency?18) Which EM wave has the most energy?19) Which three EM waves are ionising?20) What happens when light travels from air
into a glass block?21) What happens when light travels from a
glass block into air?22) What is the law of reflection?23) What is the danger of ultra-violet radiation?
24) What is the danger of X-rays and gamma ray?
25) What are radio waves used for?26) What are microwaves used for?
27) What is infra-red used for?28) What is visible light used for?29) What is ultra-violet used for?30) What are X-rays used for?31) What are gamma rays used for?
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Waves transfer energy from one place to another.
There are two types of wave; longitudinal and transverse.
In longitudinal waves, the vibrations are parallel to the direction of wave travel.
In a longitudinal wave, the region where the particles are closest together is called a compression. The region where the particles are furthest apart is called a rarefaction. The distance between one compression/rarefaction and the next compression/rarefaction is called the wavelength.
In transverse waves, the vibrations are at right angles to the direction of wave travel.
In a transverse wave, the area of zero displacement is called the equilibrium position. The top of a wave is called the peak or crest, and the bottom of a wave is called the trough. The distance between the equilibrium position and the peak/crest is called the amplitude. The distance between one crest/trough and the next crest/trough is called the wavelength.
Place the following waves in the correct column opposite:
Light Sound Ultra-violet Ultra-sound Ripples on water All EM waves
Transverse Longitudinal
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Basic:
1. What do waves transfer?2. What are the two types of wave?3. Cross out the wrong one:
- Transverse waves vibrate parallel / at right angles to the direction of energy transfer- Longitudinal waves vibrate parallel / at right angles to the direction of energy transfer
4. The wave below is transverse / longitudinal. Label the wave.
5. The wave below is transverse / longitudinal. Label the wave.
Medium: Draw a line
WavelengthAmplitudeCrestTroughCompressionRarefaction
For each wave described below, identify the wave as a transverse or longitudinal wave.
1. The wave created by moving the end of a spring toy up and down. 2. The wave created by moving the end of a spring toy back and forth parallel to the length of the spring. 3. A sound wave. 4. An ocean wave. 5. An electromagnetic wave.
Height of a waveBottom of a waveTop of a waveDistance between two wavesWhere particles are closest togetherWhere particles are furthest apart
Hard: Use complete sentences. Look at the number of marks available.
1. Describe the differences between longitudinal waves and transverse waves (3). 2. Radio waves are electromagnetic waves. Describe how radio waves are different from sound waves. (4)
3. Describe how switching the desk lamp on and off shows that light waves transfer energy. (2)
(a) Figure 1 shows two waves.
(i) Name one wave quantity that is the same for the two waves. (1)
______________________________________________________________
(ii) Name one wave quantity that is different for the two waves. (1)
______________________________________________________________
(iii) The waves in Diagram 1 are transverse.
Which one of the following types of wave is not a transverse wave?
Draw a ring around the correct answer. (1)
Figure 2 shows a longitudinal wave being produced in a stretched spring.
Figure 2
(b) Which of the letters on Figure 1 shows the centre of a rarefaction? (1)
J K L M
(b) Which two letters in Figure 1 have a distance of one wavelength between them? (1)
J and K K and L L and M J and M
(d) Describe how the end of the stretched spring should be moved in order to produce a transverse wave. (1)
gamma rays sound visible light
_______________________________________________________________________
The time period is similar to the wavelength, but is a measure of how long it takes a wave to travel a wavelength.
The frequency measures how many waves travel past a point every second. The equation that links time period and frequency is:
T = 1 ÷ f
where T is the time period (in seconds)
f is the frequency (in Hertz)
Stretch:
a) How many waves are on the diagram?
b) What is the time period of the wave?
c) What is the frequency of the wave?
The larger the amplitude, the louder the sound
The smaller the wavelength, the higher the pitch of the sound
Example question 1) Which of these waves is louder? Why?
Time period and frequency
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Example question 2) Which of these waves has a higher pitch? Why?
Basic
Q1: Write the equation that links time period and frequency.
Q2: What are the units of time period and frequency?
Q3: Calculate the time period when the frequency is:
a) 10 Hz b) 5 Hz c) 0.2 Hz d) 1200 Hz e) 0.006 Hz
Q4: What is the definition of frequency?
Medium
Q5: Rearrange the equation to give an equation for frequency.
Q6:
Hard
Q7: A note is played on an electric keyboard. The frequency of the note was 440 Hz. What does a frequency of 440 Hz mean?
Q8: Calculate the time period when the frequency is:
a) 2 kHz. b) 0.5 kHz c) 150 kHz d) 0.2 kHz e) 0.01 kHz
Q9: Calculate the frequency when the time period is:
a) 0.5 seconds b) 0.01 seconds b) 5 milliseconds c) 2 millisecondsd) 1 minute e) 30 minutes f) 1 hour g) 1 year.
To go from kHz to Hz → × 1000
To go from milliseconds to seconds → ÷ 1000
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Q10: What is the time period of the wave opposite?
Q11 Using the answer to Q10, what is the frequency of the wave opposite?
Q1. The teacher places a microphone near the pupil as she plays her flute. The diagram below shows the pattern on an oscilloscope screen.
The pupil then plays her flute at a higher pitch and more quietly.Which diagram below shows the pattern that would be seen on the oscilloscope?
Tick the correct box.
1 mark
Q2. The diagrams below show the patterns produced on an oscilloscope by threedifferent sound waves.
(i) Which two waves have the same loudness?Write the letters.
............ and ............
How do the diagrams show this?
...............................................................................................................
............................................................................................................2 mark
(ii) Which two waves have the same pitch?Write the letters.
............ and ............
How do the diagrams show this?
...............................................................................................................
.............................................................................................................2 mark
[5]
The wavelength equation says that the velocity of a wave is equal to the frequency multiplied by the wavelength:
v=f × λ
where v is the velocity (m/s)
f is the frequency (Hz)
λ is the wavelength (m)
Example question: A wave has a frequency of 12 kHz and a wavelength of 20 cm. Calculate the wave speed.
Step 1: Write the equation. v=f × λ
Step 2: Write down the variables
f = 12 kHz = 12,000 Hzv = 20 cm = 0.2 m Step 3: Calculate the answer
v = 12,000 × 0.2 = 2400 m/s
The speed of light is always constant at 300,000,000 m/s (3 x 108 m/s).
Nothing can travel faster than this.
The wave equation
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All electro-magnetic waves travel at the speed of light.
Stretch: Sound travels a distance of 686 m in a time of 2 seconds. Calculate the speed of sound.
How does it compare to the speed of light? Task: Complete in your exercise book
Basic
Q1. Write down the wave equation.
Q2. Write down the units and symbols for velocity, frequency and wavelength.
Q3. What is the wave speed if:
a) f = 5 Hz, λ = 1 m b) f = 6 Hz, λ = 0.25 m c) f = 10 Hz, λ = 0.2 m
d) f = 0.01 Hz, λ = 25 m e) f = 2000 Hz, λ = 4 m f) f = 0.05 Hz, λ = 80 m
Medium (need to rearrange equations)
Q4. Re-arrange the equation to give two equations for f and λ.
Q5. What is the wave frequency if:
a) v = 5 m/s, λ = 1 m b) v = 330 m/s, λ = 0.01 m c) v = 1,500 m/s, λ = 0.5 m
d) v = 0.1 m/s, λ = 80 m e) v = 17 m/s, λ = 0.1 m f) v = 300,000,000 m/s, λ = 0.002 m
Q6. What is the wavelength if:
a) f = 25 Hz, v = 2 m/s b) f = 15 Hz, v = 0.1 m/s c) f = 1,800 Hz, v = 0.2 m/s
d) f = 22 Hz, v = 2 m/s e) f = 1,300 Hz, v = 20 m/s f) f = 6,500,000 Hz, v = 343 m/s
Hard (word questions with unit conversions)
Q7. A sound wave has a frequency of 3.43 kHz and a wavelength of 0.1m. Calculate the speed of sound.
Q8. Dr. Edmunds (strangely) decides to sing to the class and sings with a frequency of 6.86 kHz and a wavelength of 0.05 m. Calculate the speed.
Q9. A wave has a speed of 550 m/s and a frequency of 11 kHz. Calculate the wavelength.
Q10 A wave has a speed of 250 m/s and a frequency of 15 kHz. Calculate the wavelength.
Q11 The speed of any EM wave is 300,000,000 m/s. Calculate the frequency of a radio wave with wavelength of 10 cm.
Q12 Microwaves are a transverse wave of wavelength 0.05 cm. Calculate the frequency of a microwave.
To go from kHz to Hz → × 1000
To go from cm to m → ÷ 100
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Q1.A note was played on an electric keyboard.
The frequency of the note was 440 Hz.
(a) (i) What does a frequency of 440 Hz mean?
______________________________________________________________
______________________________________________________________(1)
(ii) The sound waves produced by the keyboard travel at a speed of 340 m / s.
Calculate the wavelength of the note.
Give your answer to three significant figures.
______________________________________________________________
______________________________________________________________
______________________________________________________________
Wavelength = ____________________ metres(3)
(b) Figure 1 shows a microphone connected to a cathode ray oscilloscope (CRO) being used to detect the note produced by the keyboard.
Figure 1
Figure 2 shows the trace produced by the sound wave on the CRO.
Figure 2
A second note, of different wavelength, was played on the keyboard.
Figure 3 shows the trace produced by the sound wave of the second note on the CRO.
Figure 3
The settings on the CRO were unchanged.
What two conclusions should be made about the second sound wave produced by the keyboard compared with the first sound wave?
Give a reason for each conclusion.
Conclusion 1 ________________________________________________________
___________________________________________________________________
Reason ____________________________________________________________
___________________________________________________________________
Conclusion 2 ________________________________________________________
___________________________________________________________________
Reason ____________________________________________________________
___________________________________________________________________(4)
(Total 8 marks)
To measure the wavelength of a wave in a ripple tank, use a ruler and take a picture with a camera.
Example question:
a) Use just one wave from the photo to get the wavelength of a wave.
b) Now use ten and take an average. Which is more accurate?
To measure the frequency count the number of waves that pass a point in 10 seconds and divide by 10. We can record it and play back in slow motion.
Ripple tank practical
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Example question: If 15 waves pass a point in 10 seconds, then the frequency is 15 ÷ 10 = 1.5 Hz
Mini-task. Calculate the frequency if:
1) 120 waves pass every 10 seconds
2) 5 waves pass every 10 seconds
3) 1500 waves pass every 10 seconds.
When we’ve measured the frequency and the wavelength we can use the wave speed equation to calculate the speed of the wave.
Mini-task.
1) What is the wave speed equation?2) The measured frequency was 10 kHz and the measured wavelength was
15 mm. Calculate the speed of the wave.
Task: Complete in your exercise book
Basic
Q1. How do we measure the wavelength of a wave in a ripple tank?
Q2. How do we measure the frequency of a wave in a ripple tank?
Q3. Once we’ve measured the frequency and the wavelength of a wave in a ripple tank, how do we find out the wave speed?
Medium
Q4. Why is it a benefit to measure the length of ten wavelengths and then take an average?
Q5. Calculate the frequency if: a) 50 waves pass a point in 10 seconds.
b) 20 waves pass a point in 2 seconds.
c) 100 waves pass a point in 20 seconds.
Q6. The measured frequency of a wave is 5 Hz. Calculate the wave speed for each of the wavelengths:
a) 0.1 mb) 20 cmc) 2 mm
Q7. The measured wavelength is 0.02m. Calculate the wave speed for each of the frequencies:
a) 10 Hz
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b) 0.2 kHzc) 5 kHz
Hard
A ripple tank is used to investigate the behaviour of water waves. A bar moves up and down to make the waves.Q8. What is the wavelength of each wave in the diagram?
Q9. The ripple tank produces 10 waves in 2 seconds. What is the frequency of the waves?
Q10. The bar is made to move faster. It now produces waves with a frequency of 20 Hz and a wavelength of 0.5 cm. Calculate the speed of the waves in units of cm/s.
Q11. A student uses the ripple tank to investigate the relationship between depth of water and speed of waves. The graph shows the student’s results.
There is one anomalous result. On the graph, draw a ring around the anomalous result.
Q12. On the graph, draw a line of best fit.
Q13. Use your line of best fit to find the speed of a wave at a depth of 20cm.
Q1.Small water waves are created in a ripple tank by a wooden bar. The wooden bar vibrates up and down hitting the surface of the water.
The figure below shows a cross-section of the ripple tank and water.
(a) Which letter shows the amplitude of a water wave? (1)
___________________________________________________________________
(b) The speed of the wooden bar is changed so that the bar hits the water fewer times each second.
What happens to the frequency of the waves produced? (1)
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(c) Describe how the wavelength of the water waves in a ripple tank can be measured
accurately. (2)
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(d) The water waves in a ripple tank have a wavelength of 1.2 cm and a frequency of 18.5 Hz.
How does the speed of these water waves compare to the typical speed of a person walking?
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All EM waves reflect if they hit a reflective surface. Light is the most common example of this and it’s how we can see ourselves in a mirror.
Law of Reflection:
Angle of incidence (°) = angle of reflection (°)
i (°) = r (°)
The law of reflection is true for any type of wave being reflected from a surface.
Reflection
Put your mirror carefully on the line labelled ‘mirror’. Draw a line from each dot to the point where the normal line meets the mirror. Shine your light ray along
this line and then draw another line to show where the reflected ray is.
Measure the angles using a protractor and fill in the table below:
Angle of incidence (°) Angle of reflection (°)
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Plot your results on the graph below.
Q1.The diagram below shows the apparatus a student used to investigate the reflection of light by a plane mirror.
The student drew four ray diagrams for each angle of incidence.
The student measured the angle of reflection from each diagram.
The table below gives the student’s results.
Angle of reflection
Angle of incidence Test 1 Test 2 Test 3 Test 420° 19° 22° 20° 19°30° 31° 28° 32° 30°40° 42° 40° 43° 41°50° 56° 49° 53° 46°
(a) For each angle of incidence, the angle of reflection has a range of values.
This is caused by an error.
What type of error will have caused each angle of reflection to have a range of values?
___________________________________________________________________(1)
(b) Suggest what the student may have done during the investigation to cause each angle of reflection to have a range of values.
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___________________________________________________________________(1)
(c) Estimate the uncertainty in the angle of reflection when the angle of incidence is 50°.
Show how you determine your estimate.
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Uncertainty = ± _____________________ °(2)
(d) The student concluded that for a plane mirror, the angle of incidence is equal to the angle of reflection.
Explain whether you agree with this conclusion.
Use examples from the results in the table below in your answer.
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(e) What extra evidence could be collected to support the student’s conclusion?
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___________________________________________________________________(1)
(f) State one change the student should make to the apparatus if he wants to use the same method to investigate diffuse reflection.
___________________________________________________________________
___________________________________________________________________(1)
(Total 8 marks)
When an EM wave (like light) travels into a material that is more dense (for
Refraction
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example from air into a glass block), it refracts towards the normal (an imaginary line at right angles to the surface). This is because light travels slower in objects that are more optically dense.
Label the diagram below:
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Refraction can also be shown with wavefronts.
In a more dense material (like glass) the wave travels more slowly. The wavelength therefore decreases.
Waves can be absorbed, transmitted, reflected or refracted when travelling from one object to another.
Which of the diagrams show absorption, transmission, reflection and refraction?
Aim: To investigate how angle of incidence affects angle of refraction
Prediction:
I predict that as the angle of incidence increases, the angle of refraction will increase/decrease.
Equipment:
Method1. Put a piece of plain ________ on the desk. (use the blank page opposite)2. Set up a power pack and ____ _______ so that a single ray of light is shining across
the plain ________.3. Place a rectangular _________ _________ on the paper.4. Draw around the ______ ___________.5. Draw a normal line at _______ ________ to the block. 6. Shine the ray of light into the _________ line.7. Using a ________, put small crosses to show where the rays of light go.
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8. Take the __________ __________ off the paper. Use a ________ to join the crosses and show the path of the light.
9. Use a ___________ to measure the angles of incidence and the angles of refraction from the normal.
Results
Light entering the block Light leaving the block
Angle of incidence Angle of refraction Angle of incidence Angle of refraction
Q1.The data given in the table below was obtained from an investigation into the refraction of light at an air to glass boundary.
Angle of
incidenceAngle of
refraction20° 13°
30° 19°
40° 25°
50° 30°
(a) Describe an investigation a student could complete in order to obtain similar data to that given in the table above.
Your answer should consider any cause of inaccuracy in the data.
A labelled diagram may be drawn as part of your answer.
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(b) State the reason why light is refracted as it crosses from air into glass.
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___________________________________________________________________(1)
(Total 7 marks)
The electro-magnetic (EM) spectrum is a family of 7 waves.
They are all transverse and travel at the speed of light.
Electromagnetic Waves
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Mini task:
1. Which wave has the longest wavelength?
2. Which wave has the highest frequency?
3. Which wave has the highest energy?
4. Which wave has the biggest hazard?
The three EM waves with the most energy are ionising:
• UV
• X-rays
• Gamma rays
The order of visible light: ROY G. BIV
Task: Complete in exercise book
Basic
1. How many EM waves are there?2. All EM waves are transverse/longitudinal?3. What speed do EM waves travel at?4. List the EM waves in order (from longest wavelength to shortest wavelength). What
is the mnemonic we use to memorise this?5. Write the order of the colours in visible light (from longest wavelength to shortest
wavelength).6. Which EM wave:
a) Has the longest wavelength?b) Has the highest frequency?c) Has the least energy?
7. What three EM waves that are ionising? Describe what ionisation is.
Medium
8. What wave(s) have more energy than ultraviolet?9. What wave(s) have a longer wavelength than infrared?10.Describe why ionising radiation can be harmful. 11.Microwaves and visible light are two types of EM wave. Both can be used for
communications. Give two properties that are common to both visible light and microwaves.
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Hard
12.We use ultrasound to scan unborn babies, and not X-rays. Explain why we do not use X-rays to scan unborn babies.
13.Describe the differences between visible light waves and sound waves. 14.Mobile phones send signals using microwaves. Explain why most people believe that
these microwaves are not harmful to health. 15.A mobile phone network uses microwaves to transmit signals through the air. The
microwaves have a frequency of 1.8 × 109 Hz and travel at a speed of 3.0 × 108 m/s. Calculate the wavelength of the microwaves.
16.Dr. Edmunds used to work with a “frequency-doubled Nd:YAG” laser. This emitted scary green light at a wavelength of 532nm. Calculate the frequency of this light.
17.Dr. Edmunds also used to work with an even scarier CO2 laser which he definitely didn’t accidentally set fire to a computer monitor with once. Nope. That definitely didn’t happen. It had a wavelength of 10.6 μm. Calculate the frequency of this laser.
18.A thunderstorm is happening near HAB. The thunder is heard a time of 15 seconds after the lightning. How far away is the thunderstorm?
Q1. The diagram shows some of the kinds of waves in the electromagnetic spectrum.Choose words from this list to complete the empty boxes on the diagram. (3)
alpha radiation infrared radiation radio waves X-rays
Q2. Infrared and microwaves are two types of electromagnetic radiation.
The diagram below shows the positions of the two types of radiation within part of the electromagnetic spectrum.
(a) Name one type of electromagnetic radiation which has more energy than infrared. (1)
___________________________________________________________________
(b) Use the correct answer from the box to complete each sentence.
Each answer may be used once, more than once or not at all. (3)
nm → m × 10-9
μm → m × 10-6
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greater than less than the same as
The wavelength of infrared is ____________ the wavelength of microwaves.
The frequency of microwaves is ____________ the frequency of infrared.
The speed of microwaves in a vacuum is ____________ the speed of infrared in a vacuum.
Q3. (a) Which one of the following is not an electromagnetic wave? (1)
Tick one box.
Gamma rays
Sound
Ultraviolet
X-rays
(b) What type of electromagnetic wave do our eyes detect? (1)
___________________________________________________________________
Scientists have detected radio waves emitted from a distant galaxy.
Some of the radio waves from the distant galaxy have a frequency of 1 200 000 000 hertz.
(c) Which is the same as 1 200 000 000 hertz? (1)
Tick one box.
1.2 gigahertz
1.2 kilohertz
1.2 megahertz
1.2 millihertz
(d) Radio waves travel through space at 300 000 kilometres per second (km/s).
How is 300 000 km/s converted to metres per second (m/s)? Tick one box. (1)
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300 000 ÷ 1000 = 300 m/s
300 000 × 1000 = 300 000 000 m/s
300 000 + 1000 = 301 000 m/s
300 000 – 1000 = 299 000 m/s
(e) Write the equation which links frequency, wavelength and wave speed. (1)
___________________________________________________________________
(f) Calculate the wavelength of the radio waves emitted from the distant galaxy.
Give your answer in metres. (3)
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Radio waves are used for radio/TV transmissions. They are used for this purpose because they are long wavelength and can diffract (bend) around large objects. They are reflected from a part of the atmosphere called the ionosphere and so travel long distances.
Microwaves are used in microwave ovens (duh!), mobile phones and satellite communication (as they can travel through the ionosphere). A danger of microwaves is that they can cause internal tissue heating.
Infrared is used in remote controls, heating and in night vision (because warmer objects give out more infrared). A danger of infred is skin burns.
Light is used for seeing, in devices that look inside our body (called endoscopes) and for fibre-optic communication. The danger of light is blindness. This is why you should never look directly into the Sun.
Ultraviolet is used in sun beds and in security marking on bank notes. Too much ultraviolet can cause sun burn (sun cream works by absorbing U-V). As ultraviolet is ionising it can damade/mutate cells and cause cancer.
X-rays are used to image luggage and to X-ray broken bones. X-rays are also ionising and so X-rays should not be taken of pregnant women. Instead ultra-sound scans are used as ultra-sound is not ionising.
X-rays are absorbed by dense structure like bone (but go through less dense objects). X-rays show up on film or charge-couple device (CCD).
Gamma radiation is used to sterlise food and medical equipment. It can also be used in radiotherapy to kill cancerous cells. Gamma is the most ionising out of all the EM waves.
Uses of Electromagnetic Waves
Basic: Match up the following parts of the EM spectrum with their uses
Gamma rays Allow us to see
Radio waves Remote Controls
Ultra Violet ‘See’ broken bones
Visible Carry TV signals
Microwaves Mobile phones
X rays Sterilise equipment
Infra Red Causes sun burn
Medium
1. What is the danger of:a) Visible lightb) Infra-redc) Microwaves
2. Which three EM waves are ionising? What does ionising mean and what is it dangerous?
3. What does sterilisation mean? What property of gamma waves makes it suitable for sterilising food/medical equipment?
4. What does sun-screen do to UV light?5. Different parts of the EM spectrum are useful
for different methods of communication. The diagram shows a transmitter emitting two electromagnetic waves L and M. a) i) Wave L is used to send a signal to a satellite. Which part of the electromagnetic spectrum does wave L
belong to?ii) What name is given to the process that occurs as wave L passes into the ionosphere?
b) I) Wave M is reflected by the ionosphere. On the diagram above, draw the path of wave M until it reaches the receiver. ii) On the diagram above, draw a line to show the normal where wave M meets the ionosphere. Label the line N.
c) Give two properties of all electromagnetic waves.
Hard
6. The photo shows an X-ray of an arm with a broken bone.a) Complete the following sentence. X-
rays are part of the ________________ spectrum.
b) The graph shows how the intensity of the X-rays changes as they pass through soft tissue and reach a
detector. i) Use the graph to determine the intensity of X-rays
reaching the detector for a 3cm thickness of soft tissue. ii) Describe how the thickness of soft tissue affects the
intensity of the X-rays. iii) The data in the graph is shown as a line graph and not as a bar chart. Explain why.
c) What happens to X-rays when they enter a bone?d) How are images formed electronically in a modern X-ray machine?
e) Radiographers who take X-ray photographs may be exposed to X-rays. X-rays can increase the risk of the radiographer getting cancer. Why can X-rays increase the risk of getting cancer?
f) What should the radiographer do to reduce the risk from X-rays?
Q1.The figure below shows an incomplete electromagnetic spectrum.
A microwaves B C ultraviolet D gamma
(a) What name is given to the group of waves at the position labelled A in the figure above?
Tick one box.
infrared
radio
visible light
X-ray
(1)
(b) Electromagnetic waves have many practical uses.
Draw one line from each type of electromagnetic wave to its use.
Electromagnetic wave Use
For fibre optic communications
Gamma rays
For communicating with a satellite
Microwaves
To see security markings
Ultraviolet
To sterilise surgical instruments
(3)
(c) Complete the sentence.
Use an answer from the box.
black body ionising nuclear
X-rays can be dangerous to people because X-rays are
_____________________ radiation.(1)
(Total 5 marks)
Q2.Diagram 1 shows four of the seven types of wave in the electromagnetic spectrum.
Diagram 1
J K L Visiblelight Infrared Microwaves Radio
waves
(a) The four types of electromagnetic wave named in Diagram 1 above are used for communication.
(i) Which type of electromagnetic wave is used when a traffic signal communicates with a car driver?
______________________________________________________________(1)
(ii) Which type of electromagnetic wave is used to communicate with a satellite in space?
______________________________________________________________(1)
(b) Gamma rays are part of the electromagnetic spectrum.
Which letter, J, K or L, shows the position of gamma rays in the electromagnetic spectrum?
Draw a ring around the correct answer.
J K L
(1)
(c) Diagram 2 shows an infrared wave.
Diagram 2
(i) Which one of the arrows, labelled A, B or C, shows the wavelength of the wave?
Write the correct answer, A, B or C, in the box.
(1)
(ii) Draw a ring around the correct answer to complete the sentence.
shorter than
The wavelength of infrared waves is the same as the wavelength
longer than
of radio waves.(1)
(d) Mobile phone networks send signals using microwaves. Some people think the energy a person’s head absorbs when using a mobile phone may be harmful to health.
(i) Scientists have compared the health of people who use mobile phones with the health of people who do not use mobile phones.
Which one of the following statements gives a reason why scientists have done this?
Tick ( ) one box.
To find out if using a mobile phone is harmful to health.
To find out if mobile phones give out radiation.
To find out why some people are healthy.
(1)
(ii) The table gives the specific absorption rate (SAR) value for two different mobile phones.
The SAR value is a measure of the maximum energy a person’s head absorbs when a mobile phone is used.
Mobile Phone SAR value in W/kg
X 0.28
Y 1.35
A parent buys mobile phone X for her daughter.
Using the information in the table, suggest why buying mobile phone X was the best choice.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________(2)
Heat can move by travelling as infrared waves.
Infrared waves heat objects that absorb them and so can be called thermal radiation.
Matt black surfaces are the best absorbers and emitters of radiation.
Shiny surfaces are the worst absorbers because they reflect most of the radiation away and the worst emitters.
An object called a Leslie cube can help show this. A Leslie cube is a metal can with one silvered side and one matt black side. There is a hole in the hole so that it can be filled with hot water.
The matt black side is a better emitter of IR radiation and so a thermal camera or IR thermometer shows a greater temperature.
This can also be shown by using an aluminium can, with one side painted matt black.
Basic
Infra-Red radiation
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1. How do infrared waves heat objects?2. What is another name for infrared waves?3. Which type of surface is the best absorber of infra-red radiation?4. Which type of surface is the worst absorber of infra-red radiation?5. Which type of surface is the best emitter of infra-red radiation?6. Which type of surface is the worst emitter of infra-red radiation?7. Using the diagram opposite, which of the metal plates (J, K or L) will have the hottest temperature after
being heated for 5 minutes. Explain why.
Medium
8. The diagram to the left shows an experiment to find out what happens to infrared waves when they strike different surfaces. The water in the black tube gets hotter than the water in the shiny tube. Choose words from the list to complete the sentences
below.
9. The metal sheets in the diagram to the left absorb infrared radiation. The wax melts and the drawing pins fall off the surfaces. a) Draw one line from each variable to the
correct description of that variable.
b) The drawing pin attached to the matt black metal sheet fell off first. What can be concluded from this result?
Hard
10. a) A company is developing a system which can heat up and melt ice on roads in the winter. During the summer, the black surface of the road will heat up in the sunshine. This energy will be stored in a large amount of soil deep under the road surface. Pipes will run through the soil. In winter, cold water entering the pipes will be warmed and brought to the surface to melt ice. The system could work well because the road surface is black. Suggest why.
b) What is meant by specific latent heat of fusion?
c) Calculate the amount of energy required to melt 15 kg of ice at 0°C. Specific latent heat of fusion of ice = 3.4 × 105 J/kg.
The diagram shows the design of a solar cooker. The cooker heats water using infrared radiation from the Sun.
(a) Why is the inside of the large curved dish covered with shiny metal foil? (1)
___________________________________________________________________
___________________________________________________________________
(b) Which would be the best colour to paint the outside of the metal cooking pot?
Draw a ring around the correct answer.
black silver white
Give a reason for your answer. (2)
___________________________________________________________________
___________________________________________________________________
(c) Why does the cooking pot have a lid? (1)
___________________________________________________________________
(d) Calculate how much energy is needed to increase the temperature of 2 kg of water by 80 °C. (3)
The specific heat capacity of water = 4200 J/kg °C.
___________________________________________________________________
___________________________________________________________________
Energy = ___________________________________
Radio waves are produced when an alternating current is passed through a wire in a radio transmitter. The oscillating (vibrating) particles in the wire produce a radio wave which is modulated and boosted so it can carry the signal over a great distance.
When this radio signal reaches another antenna (e.g. aerial on a radio) the radio waves cause oscillations in the wire. This produces an alternating current of the same frequency as the radio signal.
Sound waves can travel through solids causing vibrations in the solid.
When a sound wave reaches the ear drum, it causes the ear drum to vibrate.
Radio & sound waves
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The range of frequencies that a human can hear is called the auditory range. Humans can hear from 20 – 20,000 Hz.
Basic
1. What produces a radio wave?2. How is an electronic signal produced from an
antenna?3. What happens when a sound wave reaches the
ear drum?4. What is the auditory range of humans? 5. Join up parts of the ear with their correct
description below.
Medium
6. What is the name for the range of frequencies that an animal can hear?
7. Use the graph to the right to find the answers to these questions. a) What’s the highest frequency that a dog can hear?b) Which animal can hear the highest pitch sounds?c) Which animal can hear the widest range of
frequencies.
8. a) Which mammal in the table can hear the highest frequency?b) Which mammal in the table, apart from humans, cannot hear ultrasound?
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c) Give one example of a frequency which an elephant can hear but which a tiger cannot.
Hard
9. a) What makes microwaves suitable for sending communications to a satellite in space?b) Scientists have detected short bursts of radio waves emitted from a distant galaxy. The scientists think that the radio waves may have been emitted from a neutron star. What even leads to a neutron star forming?c) Some of the radio waves from the distance galaxy have a frequency of 1.2 GHz. Convert 1.2 GHz into Hz. d) Radio waves travel through space at the speed of light. Calculate the wavelength of the 1.2 GHz radio waves emitted from the distant galaxy. e) When radio waves are absorbed by an aerial they may create an alternating current in an electrical circuit. If an alternating current is created what frequency would it have?
(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?
______________________________________________________________
______________________________________________________________(1)
(iii) Ultrasound can be used to find the speed of blood flow in an artery.
State one other medical use of ultrasound.
______________________________________________________________(1)
(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.
___________________________________________________________________
___________________________________________________________________
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. (2)
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
White light is made up of a spectrum of all the colours:
ROYGBIV.
This can be shown by putting white light into a glass prism. Where we can see the separation of colours as violet refracts the most (because it has the shortest wavelength). You can remember this by saying violet bends most violently. Red refracts the least as it has the longest wavelength. We can therefore see the individual colours in the spectrum. This is called dispersion.
A colour filter only allows one colour of light to pass through it. The filter absorbs the other colours so they do not pass through.
Filters can be used to “block” out different colours of light.
Remember - white light is made up of a combination of different colours.
Colour
Coloured objects only reflect their own colour light. They then seem this colour because that colour is what is reflected into our eyes.
Basic
1. White light is made up of a __________ of all the colours. 2. Write the order of the colours of visible light, from longest wavelength to shortest wavelength. 3. What colour of light is let through the following filters:
a) White light through a red filter. b) White light through a green filter. c) White light through a blue filter. d) White light through a green then a blue filter.
4. Write what colour the following objects will look like:a) White light on a red object. b) White light on a green object. c) Green light on a red object. d) Red light on a blue object.
Medium
5. Which colour refracts the most? Which refracts the least?6. For the items of clothing in the table below, write down the colours that they would look in the different
lights shown. Some have been done for you.
7. A trainee lighting technician is trying to mix red and green light. The trainee places a red and green filter in front of a white spotlight. The diagram shows how this has been set up. a) No light reaches the screen. Explain why. b) The trainee lighting technician cuts a circle in the
red filter. What will be seen on the screen now?
Hard
8. The visible light spectrum has a range of frequencies. The diagram shows that the frequency increases from red light to violet light.
a) As the frequency of the light waves increases the wavelength of the light waves ________________ and the energy of the light waves _____________.
b) Bottled beer will spoil if the intensity of the light passing through the glass bottle into the beer is too high. The graph shows the intensity of the light that is transmitted through three different pieces of glass.
The pieces of glass all had the same thickness. Suggest why. c) Bottles made of brown glass are suitable for storing beer.
Suggest why. d) Calculate the frequency of light of wavelength 650nm.
(a) Peter had two different coloured tennis balls as shown below.
He shone white light through a red filter onto each ball.
(i) experiment 1
The white ball appeared red.Explain why this ball appeared red (2)
______________________________________
______________________________________
______________________________________
(ii) experiment 2
What colour did this ball appear? (1)
_______________________________
Explain your answer. (2)
________________________________________________________________________________
________________________________________________________________________________
(b) Peter set up a different experiment.
He cut three holes in a piece of card.
Two of the holes were covered by coloured filters as shown below.
Peter placed a red filter between the piece of card and a white screen.
He shone white light at the piece of card
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with three holes in it.
What would Peter see on the screen? (1)
________________________________
________________________________
________________________________
A converging lens is convex (it bulges outwards). It causes parallel rays to converge to a focus through refraction. The symbol for a convex lens is
The image produced by a convex lens can be either real or virtual. The image is real if it can be projected onto a screen, but virtual if it cannot.
The region where the rays converge is called the focus and the distance between this region and the lens is called the focal length.
Three rules for drawing convex lens ray diagrams:
1. Parallel Ray: A ray parallel to the optical axis passes through the focal point on the other side of the lens
2. Centre Ray: A ray that passes through the centre of the lens continues with no change in direction
Convex lenses
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3. Focal Ray: A ray that passes through the focal point emerges parallel to the optical axis on the other side of the lens
Fill in the table below using the worked examples:
Object position
Image position
Real or virtual
Magnified or diminished?
Inverted or upright?
> 2F
at 2F
Between 2F and F
At F
Between F and lens
Object >2F away. The image (I) is formed between F and 2F away from the lens and is inverted and diminished.
This could be used in a camera/eye lens.
Object at 2F. The image (I) is formed at 2F away
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from the lens, is inverted and the same size. Could be used in a photocopier.
Object between 2F and F. The image (I) is formed further than 2F away from the lens, is inverted and magnified. Could be used in a projector or a magnifying glass.
Object at F. The image (I) is formed at infinity – the rays never meet. We use this set-up for searchlights.
Object between F and lens. The virtual image (I) is formed on the same side of the lends as the object. It is the right way up and magnified.
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Task: Complete in your exercise book.
Basic
1. What does a convex lens look like? What does it cause parallel rays of light to do?2. Draw the symbol for a convex lens. 3. What does a lens change the direction of light?4. What type of images can be produced by a convex lens?
Rules for ray diagram construction:
1. Parallel Ray: A ray parallel to the optical axis passes through the focal point on the other side of the lens2. Focal Ray: A ray that passes through the focal point emerges parallel to the optical axis on the other side of
the lens3. Centre Ray: A ray that passes through the centre of the lens continues with no change in direction
Medium
Construct a ray diagram to show where the image is formed Describe the image formed (e.g. is it real or virtual and how does its size compare to the object).
Hard
1. A light bulb is placed between a convex lens and the principle focus of this lens, at position N shown in the diagram. The light bulb is then moved to position M, a large distance from the lens.
Describe how the nature of the image formed changes as the light bulb is moved from position N to position M.
2. A lens is used to produce an image. The image produced is real, inverted and magnified. a) What kind of lens has been used?b) Where is the image in relation to the lens?
3. Explain the difference between a real image and a virtual image. 4. Name some uses of convex lenses. Explain what makes a convex lens suitable for each purpose.
Q1.(a) A camera was used to take a photograph. The camera contains a convex (converging)
lens.
Complete the ray diagram to show how the lens produces an image of the object.
F = Principal focus(4)
(b) State two words to describe the nature of the image produced by the lens in the camera.
1. _________________________________________________________________
2. _________________________________________________________________(2)
(Total 6 marks)
A diverging lens is concave (it caves inwards). It causes parallel rays to diverge (spread out) through refraction. The symbol for a concave lens is
The image produced by a concave lens is always virtual.
Three rules for drawing concave lens ray diagrams:
1. Parallel Ray: A ray parallel to the optical axis passes emerges as though it was coming from the focal point
2. Focal Ray: A ray that is heading towards the focal point on the other side of the lens emerges parallel to the optical axis
3. Centre Ray: A ray that passes through the centre of the lens continues with no change in direction
Concave lenses and magnification
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Magnification is when you enlarge the appearance of something.
magnification = image height ÷ object height
Stretch: An image is 20 cm, whereas the actual size of the object is 10 mm, what is the magnification?
The graph shows how a concave lens forms an image of an object.
(a) Which point on the graph above marks the position of the principal focus of the lens? (1)
A B C D
(b) Which two words describe the image? Tick two boxes. (2)
Enlarged
Inverted
Real
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Virtual
(c) Calculate the magnification produced by the lens. (2)
___________________________________________________________________
___________________________________________________________________
Magnification = ____________________
(d) Complete the sentence. (1)
decrease increase not change
As the object is moved further away from the lens, the size of
the image will __________________________ .Magnification worksheet
Basic: Rearranging needed for Q2 and Q3.
1. Calculate the magnification if:a) Image height = 5cm, object height = 1 cm b) Image height = 3m, object height = 0.2mc) Image height = 2mm, object height = 15 mmd) Image height = 2cm, object height = 2 cm.
2. Calculate the image height if:a) Magnification = 5, object height = 2 cmb) Magnification = 1, object height = 5.5 mmc) Magnification = 0.2, object height = 2.5 md) Magnification = 1,000, object height = 1.3 mm
3. Calculate the object height if:a) Magnification = 500, image height = 1,500 mmb) Magnification = 4, image height = 7cmc) Magnification = 150, image height = 2mmd) Magnification = 200,000, image height = 0.2mm
Medium: Unit conversions needed.
4. Calculate the magnification if the image height = 2m, and the object height = 5mm. 5. A human red blood cell has a size of 9μm. A microscope makes an image of size 3cm. Calculate the
magnification of the microscope. 6. A projector creates an image of size 3m from an object of size 2cm. Calculate the magnification of the
projector. 7. The HIV virus is imaged using an electron microscope. It has a size of 100 nm. If the size of the image is 3mm,
what is the magnification of the electron microscope?8. A cell membrane is 7nm thick. The magnification of an electron microscope is x800,000, how thick is the
membrane on the image?9. A mitochondrion is 3μm in size. The magnification of this is x200,000. What is the size of the mitochondrion
in the image?10. A microscope is looking at a chloroplast. The length of the chloroplast is 5mm in the image. If the
magnification is x1000, what is length of a chloroplast?
mm → m ÷ 1000
cm → m ÷ 100
µm → m ÷ 1,000,000
nm → m ÷ 1,000,000,000
Hard: Word based questions.
11. Dr. Edmunds is working on a top secret experiment to shrink himself to the size of an ant. He sets the magnification on the machine to 0.0034. If the ant is 6 mm long, how tall is Dr. Edmunds in metres?
12. Oh no! Dr. Edmunds got his calculations completely wrong (this obviously never happens in real life *cough*). He set his magnification to 34. How tall has Dr. Edmunds accidentally made himself now? (hint: use answer from last question)
13. Dr. Edmunds decides to use his new giant size to fight Godzilla, who is threatening HAB. However, Godzilla is only 50 metres tall. How much would Godzilla have to be magnified for to be the same size as giant Dr. Edmunds?
14. To stage the fight between Godzilla and Dr. Edmunds, HAB is building a boxing ring. However, the boxing ring is only 500cm wide. It needs to be 250m to stage a good fight. How much does the boxing ring need to be magnified by?
15. Whoops, the referee’s chair (Mrs. Iles-Smith has volunteered to be the referee) has accidentally been magnified as well. The chair is now 15m tall, it needs to be 750mm tall. What does the magnification factor need to be?
16. Someone takes a photo of the fight. Dr. Edmunds appears as 6cm tall in the photo, what is the magnification factor? (hint: use your answer to Q2).
Q1.The ray diagram shows the position and size of the image, I, of an object, O, formed by a lens, L.
(a) What type of lens is shown in the ray diagram?
___________________________________________________________________(1)
(b) Name the point labelled P.
___________________________________________________________________(1)
(c) The ray diagram has been drawn to scale.
Show clearly how you work out your answer.
___________________________________________________________________
___________________________________________________________________
Magnification = _______________(2)
(d) How can you tell from this ray diagram that the image is a real image?
___________________________________________________________________
___________________________________________________________________(1)
(Total 5 marks)
A perfect black body is an object that absorbs all of the radiation incident on it. It does not reflect or transmit any radiation and is the best possible emitter.
A body at constant temperature is absorbing radiation at the same rate as it is emitting radiation.
Hotter objects emit shorter wavelengths.
How could you use incandescence to explain how a conventional light bulb works?
1. A current flows through the filament.
2. The filament heats up.
3. The thermal emission of the filament moves into the visible spectrum.
Why is the incandescent light bulb not an efficient
Blackbody radiation
device for producing light?
The filament’s emission spectrum remains mostly in the infrared, even when it is at its hottest. Most of the bulb’s energy input is therefore wasted as heat.
Figure 1 shows what happens when a ray of light enters a tin can through a small hole.
(a) Explain why the small hole looks black. (2)
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(b) All objects absorb and emit radiation.
What is meant when an object is described as a perfect black body? (1)
___________________________________________________________________
___________________________________________________________________
Figure 2 shows how the intensity of different wavelengths of radiation from a hot object varies with temperature.
(c) What can be concluded from Figure 2 about how the distribution of the intensity of radiation from an object changes as the temperature of the object increases? (3)
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
(d) The wavelength at which the Sun emits the maximum intensity of radiation is approximately 5 × 10–7 m
Estimate the surface temperature of the Sun. Use Figure 2. (1)
___________________________________________________________________
(e) Figure 3 shows how the balance between the incident radiation from space and the radiation emitted by the Earth into space has changed over the last 200 years.
Figure 3
Explain how the temperature of the Earth and its atmosphere has changed over the last 200 years.
Use the information in Figure 3. (3)
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___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________ (Total 10 marks)
Ultrasound waves are partially reflected when they meet a boundary between two different media.
Ultrasound waves to be used for both medical and industrial imaging. Ultrasound is better for pre-natal scanning as it is non-ionising.
Ultrasonic testing is a type of nondestructive testing commonly used to find flaws in materials and
Waves for detection
to measure the thickness of objects. At a construction site, a technician tests a pipeline weld for defects using an ultrasonic instrument.
Echo sounding is used to measure how deep the ocean is. This is important so ships do not head into shallow waters.
Example question: A child shouts at a nearby cliff and hears their echo 1.4 s later. How far away is the cliff? Take the speed of sound = 343 m/s.
The sound travels to and from the cliff, a total distance of 2 × s
speed = distance / time
becomes: distance = speed x time
= 343 m/s x 1.4 s
= 480.2 m
= 2 × s!
Therefore distance to the cliff = 240.1 m. Task: Complete in your exercise book Speed of sound in air = 343 m/s
Basic: The distance you get is double the distance as sound needs to travel there and back. Divide your distances by two.
1. A child shouts at a nearby cliff and hears their echo 2.5s later. How far away is the cliff?2. A bat uses echolocation to navigate inside a cave. The ultrasound takes 0.4s to be heard again by the bat.
How far away is the bat from the side of the cave?3. A boat uses echo-sounding to measure how deep the again is. Calculate the depth of the ocean if a high
frequency sound wave travelling at 1,500 m/s (sound travels faster in water than air) is transmitted and received 0.5 seconds later.
4. Dr. Edmunds’ cat Lola meows near a fence. The sound of the meow takes 0.6s to return back to Lola. How far away is Lola from the fence?
5. A technician is testing a pipeline for a defect. There is an unexpected ultrasound reflection 0.0005 s after the pulse has been emitted. How far from the surface is there a defect?
Medium: Rearranging needed for Q6/7
6. Dr. Edmunds blows the whistle while on break duty. If he’s stood 50m away from the wall of the tower block, how long will it take for him to hear the echo of the whistle?
7. A submarine is 800m from the sea floor. It sends a pulse of ultra-sound to the sea floor. If the speed of sound in water is 1500 m/s, how long does it take for a pulse to return to the submarine?
distance, D
8. 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. a) The crack causes the wave to
be partially reflected. This is detected in pulse A. Use the information in the diagram to calculate the distance of the crack from the detector.
b) Pulse B is the reflection from the end of the bolt. Use the information in the diagram to calculate the distance of the detector from the end of the bolt.
c) What is the distance between the crack and the end of the bolt?
Hard: Q10 is a multi-step calculation
9. Ultrasound waves can be passed through the body to produce medical images. When ultrasound waves are directed at human skin most of the waves are reflected. If a material called a “coupling agent” is placed on the skin it allows most of the ultrasound waves to pass through the skin and into the body. a) What is ultrasound?b) Two ultrasound frequencies that are used are 1.1 MHz and 3.0 MHz. The speed of ultrasound in water is
1500 m/s. Calculate the wavelength of the 3.0 MHz waves in water. c) The coupling agent used with ultrasound is usually a gel. Water would be a good coupling agent. Suggest
why water is not used. 10. A bat emits an ultrasound wave with a frequency of 25 kHz and a wavelength of 0.0136m. If the bat hears a
reflection 0.2s later, how far is it away from an object?
Q1.X-rays and ultrasound can both be used for scanning internal organs.
(a) Ultrasound is used to scan unborn babies but X-rays are not used to scan unborn babies.
Explain why.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________(3)
(b) The behaviour of ultrasound waves when they meet a boundary between two different materials is used to produce an image.
MHz → Hz × 1,000,000
Describe how.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________(2)
(c) Figure 1 shows two pulses from a scan of an unborn baby. The emitted pulse is labelled A. The returning pulse picked up by the receiver is labelled B.
Figure 1
The closest distance between the unborn baby and the mother’s skin is 4.0 cm.Use information from Figure 1 to calculate the average speed of the pulse.
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Average speed = _______ m/s(3)
(d) Figure 2 shows an X-ray of an arm with a broken bone.
Figure 2
© emmy-images/iStock
(i) Describe how X-rays are able to produce an image of bones.
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________
______________________________________________________________(3)
(ii) Complete the following sentence.
X-rays are able to produce detailed images because their wavelength
is very _____________ .(1)
(Total 12 marks)
Two types of wave caused by an earthquake:
- Primary (P waves).
- Secondary (S waves).
P waves (push & pull) are longitudinal and travel faster in solids than liquids.
S waves (side to side) are transverse and only travel through solids.
The Earth is made of four layers. Going from the outer layer to the inner layer
Earthquakes
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these are called:
-Crust (solid earth & rocks)
-Mantle (solid)
-Outer core (liquid iron and nickle)
-Inner core (solid iron and nickle)
The temperature of the Earth increases the deeper down you go. Despite the inner core being hotter than the outer core, it is a solid because of the greater pressure on it.
One piece of evidence for the outer core being liquid is that S waves cannot travel through it. There is an “S wave shadow” on the opposite side of the Earth.
Task: Complete in your exercise book
Basic
1. What are the names of the four layers of Earth?2. Which type of earthquake wave can travel
through liquids and which cannot?3. Which type of earthquake wave travels faster?4. The graph shows how the P, S and surface
waves spread out from the epicentre of an earthquake. A and B are seismic stations.
a) Use the graph to find the time delay between the arrival of P and S waves at station A.
b) Explain why there is a time delay between the arrival of the P and S waves at station A.
c) Explain how the graph shows that the speed of surface waves is constant.
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5. Using the graph, explain why P and S waves change speed as they travel from the epicentre to stations A and B.
Medium
6. State the difference between surface waves and P and S waves.
Z, Y and Z are stations that detect seismic waves.
7. Explain why no S waves are detection at station Z. 8. Explain why P waves change direction when they
enter the outer core. 9. Use the diagram below to help you explain the
difference between how the particles move in P and S waves.
Hard
The diagram shows the first seismic signals received from an earthquake at two monitoring stations A and B.
10. What evidence is shown by the seismic data that suggests A is nearer the epicentre than B. 11. What evidence suggests P and S waves have travelled with different speeds from the earthquake?12. The time lag between the arrival of the P and S waves for a seismic station which is 100km from the epicentre of
an earthquake is 12s. Calculate the distance of the monitoring station A from the epicentre of this earthquake.
P-waves and S-waves are two types of seismic wave caused by earthquakes.
(a) Which one of the statements about P-waves and S-waves is correct? (1)
P-waves and S-waves are transverse.
P-waves and S-waves are longitudinal.
P-waves are transverse and S-waves are longitudinal.
P-waves are longitudinal and S-waves are transverse.
Seismometers on the Earth’s surface record the vibrations caused by seismic waves.
Figure 1 shows the vibration recorded by a seismometer for one P-wave.
Figure 1
(b) Calculate the frequency of the P-wave shown in Figure 1. (1)
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Frequency = _____________________ Hz
(c) Write down the equation which links frequency, wavelength and wave speed. (1)
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(d) The P-wave shown in Figure 1 is travelling at 7200 m/s.
Calculate the wavelength of the P-wave. (3)
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Wavelength = _____________________ m
(e) Explain why the study of seismic waves provides evidence for the structure of the Earth’s
core. (2)
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