Homework
Electromagnetic Waves
April 2004 Core Paper No.10b
Electromagnetic waves, such as radio waves, are used for a variety of uses
other than for communication.
(i) Name two other electromagnetic waves and describe one beneficial
use for each of them.
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(ii) Some electromagnetic waves may have harmful effects if used
inappropriately. Name two safety precautions commonly used when
handling such radiation.
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Homework
Ch 13 Page 1 of 6
September 2004 Core Paper No.10
Consider the following types of waves:
X-rays
(a)
Infrared
Sound
Radio
Microwaves
Which of the above waves:
(i) is not part of the electromagnetic spectrum?
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(ii) can be used for remote control of TV sets?
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(iii) can pass through flesh but are partially stopped by bones?
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(b) State two properties that all the electromagnetic waves have in common.
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(c)
Calculate the frequency of radio waves that are transmitted on a
wavelength of 1500m and travel at a speed of 3x108m/s.
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(d)
(i) Microwaves have everyday uses, such as in microwave ovens. Give two
advantages microwave ovens have over the conventional oven heating
method.
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(ii) Exposure of living tissue to microwaves should be avoided. Give one
reason for this.
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Homework
Ch 13 Page 2 of 6
April 2005 Core Paper No.9
All electromagnetic waves travel through a vacuum.
(a)
(i) What type of waves are electromagnetic waves, transverse or
longitudinal?
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(ii) Name one other common property of all electromagnetic waves.
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(iii) Complete the following list of electromagnetic waves in order of
increasing wavelength.
Gamma rays, ________, _________, Visible light, __________, Radio waves.
(b)
Which part of the electromagnetic spectrum:
(i) is emitted by warm objects?
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(ii) is stopped by the ozone layer in the atmosphere?
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(iii) can pass through flesh but is partly stopped by bones?
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The speed of radio waves is 3x108m/s. Calculate the frequency of the
radio waves transmitted, which have a wavelength of 1500m.
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(c)
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Homework
Ch 13 Page 3 of 6
April 2006 Core Paper No.6
Galileo Galilei was an Italian scientist who lived about 400 years ago. He tried
to measure the speed of light using two people with lanterns in their hands,
standing about 1.5km apart from each other. One person was to send a light
signal and when the second person saw the light, he had to send a signal back.
(a)
Write the equation Galileo would have used to calculate the speed of
light.
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(b) The experiment was a complete failure. Suggest one reason for this.
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(c)
Which part of the electromagnetic spectrum is associated with each of
the following?
(i) transmitting TV programmes _______________________.
(ii) sun-tanning of the skin _______________________.
(iii) detecting metal objects in luggage _______________________.
(iv) making toast _______________________.
(d)
The table below shows part of the electromagnetic spectrum.
X-rays
UV
Visible light
Microwaves
(i) Fill in diagram 7 the missing type of electromagnetic radiation.
(ii) A thermometer with a blackened bulb may be used to detect this
type of radiation. Why is the bulb covered with black material?
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(iii) Would you expect the temperature to increase, decrease or remain
the same when this type of radiation is detected?
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(iv) What does this indicate about the type of radiation present?
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Homework
Ch 13 Page 4 of 6
September 2006 Core Paper No.8
(a)
Which type of electromagnetic wave listed below has the:
(i) shortest wavelength?
(ii) lowest frequency?
(b)
__________
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Name the type of electromagnetic wave used in each of the following:
(i) used to find the position of a distant aeroplane;
(ii) stopped by the ozone layer in the atmosphere;
(iii) sending messages using a mobile phone;
(iv) cooking meat on red hot charcoal.
(c)
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The following is an extract from a newspaper about a new use for radio
waves.
(i) Explain how microwaves heat up food.
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(ii) Name the advantage that radio waves have over microwave treatment
of food.
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(iii) Name the advantage that radio waves have over chemical treatment
of food.
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Homework
Ch 13 Page 5 of 6
April 2007 Core Paper No.10
Josephine is the owner of a small DVD rental shop. She installs a money
scanner that uses electromagnetic waves to identify fake money notes.
(a)
Name the waves that are used by the scanner.
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The scanner uses waves of wavelength 3.5x10-7m. If the speed of light
is 3x108m/s, calculate the frequency of the waves.
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(b)
(c)
Electromagnetic waves are a group of waves which have some common
characteristics, for example they are all _______________ waves, all
travel at the same _______________ in vacuum, do not need a medium
to travel, but all have different _______________ and wavelength.
(d)
Besides identifying fake money, electromagnetic waves have other uses.
Fill in the table below the best type of electromagnetic waves for each
of the uses listed.
Use
Cancer treatment
Detection of fractured bones
Photography
Night vision cameras
Electromagnetic Wave
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Homework
Ch 13 Page 6 of 6