Download P4 Booklet FINAL - Highfields School, Wolverhampton

HIGHFIELDS
SCHOOL
Physics Department
OCR GCSE Physics
P4 – Radiation for Life
Student Support Booklet
Equations
P4 – Key Words
Activity
Alpha particles
Alternating current or
voltage
Ammeter
Ampere (A)
Amplitude
Atomic number
Background Radiation
Becquerels (Bq)
Beta particles
Boron control rods
Carbon-14
Chain reaction
Charge(s)
Circuit breakers
Cold fusion
Compressions
Conductors
Cosmic rays
Count rate
current
Defibrillator
Direct current
Double insulated
Average number of nuclei that decay every second
Radioactive particles which are helium nuclei (helium
atoms with no electrons so they have a positive charge).
An electric current that is not a one way flow.
Meter used in an electric circuit for measuring current
The unit used to measure electric current, often
abbreviated to amp
The distance the wave moves from its rest position
The number of protons found in the nucleus of an atom
Ionising radiation from space and rocks, especially
granite, that is around us all the time but is at a very low
level.
Unit of activity or count rate; 1 Bq = 1 count per second
Particles given off by some radioactive materials (they
have a negative charge)
Rods that are raised or lowered in a nuclear reactor to
control the rate of fission
A radioactive isotope of carbon
A reaction where the products cause the reaction to go
further or faster, e.g. nuclear fission
Can either be positive or negative. Opposite charges
attract. The same charges will repel each other.
Resettable fuses
Attempts to produce fusion at normal room temperature
that have not been validated since other scientists could
not reproduce their results.
Particles push together, increasing pressure
Electrical conductors allow electricity to flow through
them
Radiation from space that contributes to background
radiation
Average number of nuclei that decay every second
Flow of electrons in an electric circuit
Machine which gives the heart an electric shock to start
it beating regularly
An electric current that flows in one direction only.
An electric device in which there are at least two layers
of insulation between the user and the electric wires.
Earth wire
The third wire in a mains cable which connects the case
of an appliance to the ground so that the case cannot
become charged and cause an electric shock
Earthed (electrically)
Connected to the ground at 0V
Electromagnetic waves A group of waves that carry different amounts of energy
– they range from low frequency radio waves to high
frequency gamma rays
Electrostatic attraction Attraction between opposite charges
Electrostatic dust
Charged plates inside factory chimneys remove dust
precipitators
particles from smoke
Electrostatic paint
Charges paint droplets to give even coverage
sprayer
Enriched uranium
Uranium containing more of the U-235 isotope than
occurs naturally
Fission
Splitting apart, especially of large radioactive nuclei
such as uranium
Frequency
The number of waves passing a set point per second.
Fuel rods
Rods of enriched uranium produced to provide fuel for
nuclear power stations
Fuse(s)
A special component in an electric circuit containing a
thin wire which is designed to melt if too much current
flows through it, breaking the circuit
Fusion
The joining together of small nuclei, such as hydrogen
isotopes, at very high temperatures with the release of
energy
Fusion bombs
Hydrogen bombs or H-bombs based on fusion reactions
Gamma rays
Ionising electromagnetic waves that are radioactive
and dangerous to human health – but useful in killing
cancer cells.
Geiger counter
A device used to detect some types of radiation
Geiger-Muller tube
A device used to detect some types of radiation
Gel
In ultrasound scanning, placed on the skin so that nearly
all the ultrasound passes into the body and is not
reflected by the skin.
Generator
Device that converts rotational kinetic energy to
electrical energy
Granite
Mineral containing low levels of uranium
Graphite
A type of carbon used as a moderator in a nuclear
power station
Half-life
Average time taken for half the nuclei in a radioactive
sample to decay
Helium
Second element in periodic table; an alpha particle is a
Hertz (Hz)
Ionises
Ions
Isotopes
Lead
Live wire
Longitudinal wave
Mass number
Moderator
Neutral wire
Neutrons
Nuclear equation
Nuclear power stations
Nucleons
Pitch
Potential difference
Radioactive waste
Radiocarbon dating
Radiographer
Radioisotope
Radiotherapy
Rarefractions
Ratemeter
Resistance
helium nucleus
Units for measuring wave frequency
Adds or removes electrons from an atom leaving it
charged
Charged particles (can be positive or negative)
Atoms with the same number of protons but different
numbers of neutrons
Heaviest element having a stable isotope; all isotopes of
the elements above it in the periodic table are unstable
Carries a high voltage into and around the house
Wave in which vibrations are in the same direction as
the direction in which the wave moves.
The number of protons and neutrons in a nucleus
Material used to slow down neutrons in a nuclear power
station
Provides a return path for the current in a mains supply
to a local electricity substation
Small particle which does not have a charge found in
the nucleus of an atom.
Equation showing changes to the nuclei in a nuclear
reaction
Power stations using the energy produced by nuclear
fission to generate heat
Protons and neutrons (both found in the nucleus)
Whether a sound is high or low on a musical scale
Another word for voltage (a measure of the energy
carried by the electric current)
Waste produced by radioactive materials used at
nuclear power stations, research centres and some
hospitals
Method of dating some old artefacts using Carbon-14
A technician who works in a hospital radiography
department, possibly taking x-rays or treating some types
of cancer with radiation
Isotope of an element that is radioactive
Using ionising radiation to kill cancer cells in the body
Particles are further apart than usual, decreasing
pressure
A device that measures the amount of radiation
detected by a Geiger-Muller tube
Measurement of how hard it is for an electric current to
flow through a material
Rheostat
Shock
A variable resistor
Occurs when a person comes into contact with an
electrical energy source so that the electrical energy
flows through a portion of the body
Smoke detector
Device to detect smoke, some forms of which contain a
source of alpha radiation
Sparks
Type of electrostatic discharge briefly producing light
and sound
Stable (nucleus)
(nucleus) is not radioactive; it will not decay
Superconductors
Materials that conduct electricity with little or no
resistance
Tracers
A radioactive, radiation-emitting substance used to
follow movement of a particular chemical, e.g. nuclear
medicine, tracking the path of an underground pipe,
etc.
Transmitted
Radiation passing through an object
Transverse wave
Wave in which the vibrations are at right angles to the
direction the wave is moving
Ultrasound
High-pitches sounds which are too high for detection by
human ears
Uranium
Radioactive element with a very long half-life used in
nuclear power stations
Van de Graff generator A machine which uses a moving belt to accumulate
very high charges on a hollow metal globe
Variable resistor
A resistor whose resistance can change
Voltage
A measure of the energy carried by an electric current
(also called the potential difference)
Voltmeter
Instrument used to measure voltage or potential
difference in volts (V)
Wavelength (λ)
Distance between two wave peaks
x-rays
Ionising electromagnetic waves used in x-ray
photography (used to generate pictures of bones)
Module P4: Radiation for Life
P4a: Sparks
The concept of medical physics runs through this item. Electrostatics plays an important part in our lives. We investigate some of
the ideas of electrostatics and look at the problems caused.
GRADE G - D
GRADE C
GRADE B – A*
Recognise that when some
materials are rubbed they
attract other objects:
• certain types of dusting
brushes become charged and
attract dust as they pass over
it.
Recognise that insulating
materials can become
charged when rubbed with
another insulating material.
State that there are two kinds
of charge:
• positive
• negative.
Recognise that like charges
repel and unlike charges
attract.
Understand that electrostatic
phenomena are caused
by the transfer of electrons,
which have a negative
charge.
Describe static electricity in
terms of the movement of
electrons:
• a positive charge due to lack
of electrons
• a negative charge due to an
excess of electrons.
Recognise that atoms or
molecules that have become
charged are ions.
Targets for
Improvement
Describe how you can get an
electrostatic shock from
charged objects:
• synthetic clothing.
Describe how you can get an
electrostatic shock if you
become charged and then
become earthed:
• touching water pipes after
walking on a floor covered
with an insulating material e.g.
synthetic carpet.
Explain how static electricity
can be dangerous when:
• in atmospheres where
explosions could occur
e.g. inflammable gases or
vapours or with high
concentrations of oxygen
Explain how the chance of
receiving an electric shock
can be reduced by:
• correct earthing
• use of insulating mats
• using shoes with insulating
soles
• bonding fuel tanker to
aircraft.
• in situations where large
quantities of charge could flow
through the body to earth.
Explain how anti-static sprays,
liquids and cloths help reduce
Explain how static electricity
the problems of static
can be a nuisance:
electricity.
• dirt and dust attracted to
insulators (plastic containers,
TV monitors etc.)
• causing clothing to “cling”.
P4a Activities
1. Fill in the gaps using the words in the box below.
electrons
repel
moving
charge
positively
different
conductor
neutrons
friction
rubbing
protons
insulator
attract
negatively
same
……………………….. a polythene rod gives it static electricity.
Static means not ………………………..
Atoms contain negatively charged particles called
……………………….., ………………………..charged particles called
protons and neutral particles called ………………………..
When charged objects are brought near each other, they either
……………………….. or ……………………….. each other. What
happens depends on their ………………………..
Two objects with the ……………………….. charge will
……………………….. each other, whilst oppositely charged objects
will ……………………….. each other.
2. Draw an annotated diagram to show how a balloon rubbed
against your hair is then able to stick to the wall.
3. Answer the following questions on static electricity:
a) What charge does a polythene rod acquire when rubbed with
a duster?
……………………………………………………………………………………
b) Name the particles that have moved to make this happen.
……………………………………………………………………………………
c) Did these particles move from the polythene rod or from the
duster?
……………………………………………………………………………………
d) What charge does an acetate rod acquire when rubbed with
a duster and in which direction did these particles move?
……………………………………………………………………………………
e) What happens if two negatively charged objects or two
positively charged objects are brought near each other?
……………………………………………………………………………………
f) What happens if a positively charged object is brought near a
negatively charged object?
……………………………………………………………………………………
g) Jo combs her hair very hard. Some of her hair stands up a little.
Explain why this happens.
……………………………………………………………………………………
……………………………………………………………………………………
Module P4: Radiation for Life
P4b: Electrostatics
Electrostatics has many uses. This item looks at some of the uses both in medicine and everyday life and illustrates the use of
contemporary scientific and technological developments and their benefits, drawbacks and risks.
GRADE G - D
Recall that electrostatics can
be useful for electrostatic
precipitators:
• remove the dust or soot in
smoke
• used in chimneys.
GRADE C
GRADE B – A*
Explain how static electricity
can be useful for electrostatic
dust precipitators to remove
smoke particles etc from
chimneys:
• dust passes through charged
metal grid or past charged
rods
• dust particles become
charged
• plates are earthed or
charged opposite to grid
• dust particles attracted to
plates
• plates struck and dust falls to
collector.
Explain how static electricity is
used in electrostatic dust
precipitators to remove smoke
particles etc from chimneys:
• high voltage metal grids put
into chimneys to produce a
charge on the dust
• dust particles gain or lose
electrons
• dust particles induce a
charge on the earthed metal
plate
• dust particles are attracted
to the plates.
Targets for
Improvement
Recall that electrostatics can
be useful for spraying:
• spray painting
• crop spraying.
Recall that electrostatics can
be useful for restarting the
heart when it has stopped
(defibrillator).
Recall that defibrillators work
by discharging charge.
Explain how static electricity
can be useful for paint
spraying:
• spray gun charged
• paint particles charged the
same so repel giving a fine
spray and coat
• object charged oppositely to
paint so attracts paint into the
‘shadows’ of the object giving
an even coat with less waste.
Explain how static electricity
can be useful for restarting the
heart when it has stopped
(defibrillator):
• paddles charged
• good electrical contact with
patient’s chest
• charge passed through
patient to make heart contract
• care taken not to shock
operator.
Explain how static electricity is
used in paint spraying, in terms
of paint and car gaining and
losing electrons and the
resulting effects.
P4b Activities
1. Label and annotate the diagram below to show how an
electrostatic smoke precipitator works:
2. What is a defibrillator and how does it work?
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
3. Why are the handles of a defibrillator made from plastic?
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
4. Static electricity can be used in the spray painting of car
bodies.
(a)
(b)
On the diagram show the charges on the spray-paint
drops and on the car body.
Carefully explain the process.
………………………………………………………………………………...
………………………………………………………………………………...
………………………………………………………………………………...
………………………………………………………………………………...
………………………………………………………………………………...
………………………………………………………………………………...
………………………………………………………………………………...
………………………………………………………………………………...
5. Care must be taken when using electrostatics to spray-paint.
What precautions can be taken by workers when spray-painting?
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
Module P4: Radiation for Life
P4c: Safe Electrics
This item investigates electricity. Safety is a major requirement when electricity is used in a medical situation. Here the principles
of fuses and earthing are studied.
GRADE G - D
GRADE C
Explain the behaviour of simple
circuits in terms of the flow of
electric charge.
Explain how variable resistors can
be used to change the current in a
circuit:
• longer wires have more
resistance
• thinner wires have more
resistance (rheostat configured as
a variable resistor only).
Describe and recognise how
resistors can be used to
change the current in a circuit.
Describe how variable resistors
can be used to change the
current in a circuit:
• longer wires give less current
• thinner wires give less current
(rheostat configured as a
variable resistor only).
Recall that resistance is
measured in ohms.
Describe the relationships between
current, voltage (pd) and
resistance:
• for a given resistor, current
increases as voltage increases and
vice versa
• for a fixed voltage, current
decreases as resistance increases
and vice versa.
Use the equation:
GRADE B – A*
Use and apply the
equation, including a
change of subject:
𝑟𝑒𝑠𝑖𝑠𝑡𝑎𝑛𝑐𝑒 =
𝑣𝑜𝑙𝑡𝑎𝑔𝑒
𝑐𝑢𝑟𝑟𝑒𝑛𝑡
Targets for
Improvement
𝑟𝑒𝑠𝑖𝑠𝑡𝑎𝑛𝑐𝑒 =
Recall the colour coding for
live, neutral and earth wires:
• live – brown
• neutral – blue
• earth – green/yellow.
State that an earthed
conductor cannot become
live.
Describe reasons for the use of
fuses and circuit breakers (as
re-settable fuses).
Recognise that “double
insulated” appliances do not
need earthing.
𝑣𝑜𝑙𝑡𝑎𝑔𝑒
𝑐𝑢𝑟𝑟𝑒𝑛𝑡
Describe the functions of the live,
neutral and earth wires:
• live – carries the high voltage
• neutral – completes the circuit
• earth – a safety wire to stop the
appliance becoming live.
Explain how a wire fuse reduces
the risk of fire; if the
appliance develops a fault:
• too large a current causes the
fuse to melt
• preventing flow of current
• prevents flex overheating and
causing fire
• prevents further damage to
appliance.
Explain the reasons for the
use of fuses and circuit
breakers as re-settable
fuses (structure and mode
of operation not required).
Use the equation:
power = voltage × current
Explain why “double insulated”
appliances do not need earthing:
• the appliance is a non
conductor and cannot become
live.
Use the equation, including
a change of subject:
Explain how the
combination of a wire fuse
and earthing protects
people.
power = voltage × current
to select a suitable fuse for
an appliance.
P4c Activities
1. Colour in the wires then label and annotate the plug to show
how it works:
2. Complete the passage below to explain how a fuse works and
why we sometimes need an Earth wire. Use the words from the box
below:
large, harm, safety, fuse, fault, metal, surges, touch, melt, live,
circuit, fuse
Fuses are ………………… devices. If there is a fault in an appliance
which causes the ………………… and neutral (or earth) wire to
cross then a ………………… current will flow through the
………………… and cause it to ………………… . This will break the
………………… and protect the appliance and user from further
………………… .
Earth wires are always used if an appliance has a …………………
case. If there is a ………………… in the appliance, causing the live
wire to ………………… the case, the current “…………………”
down the earth wire and the …………………blows.
3. Which fuse should you use for:
(a) A 2750 W kettle running on mains electricity (230 V)? ……………
……………………………………………………………………………………
……………………………………………………………………………………
(b) A 1 kW kitchen appliance running on mains electricity? ………..
……………………………………………………………………………………
……………………………………………………………………………………
4. Give three advantages of using a RCCB (Residual Current Circuit
Breaker) over a fuse?
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
5. Complete the following sentences:
 For a given resistor, as you increase the voltage you
………………… the current.
 For a fixed voltage, as you decrease the resistance you
………………… the current.
 A longer wire will have ………………… resistance.
 A thicker wire will have ………………… resistance.
6. Use the equation sheet to help you complete the following
table:
Voltage
230 V
4 kV
1.5 kV
Current
2.6 A
10 A
0.5 mA
50 A
Resistance
220 Ω
47 kΩ
1.6 MΩ
Module P4: Radiation for Life
P4d: Ultrasound
The concept of medical physics runs through this item. Ultrasound is an important medical diagnostic and therapeutic tool. This
item looks at the properties of longitudinal waves, and investigates some of the medical uses of ultrasound.
GRADE G - D
Recall that ultrasound is a
longitudinal wave.
Recognise features of a
longitudinal wave:
• wavelength
• compression
• rarefaction.
GRADE C
GRADE B – A*
Describe features of
longitudinal waves:
• wavelength
• frequency
• compression (a region of
higher pressure)
• rarefaction (a region of lower
pressure).
Describe and compare the
motion and arrangement of
particles in longitudinal and
transverse physical waves:
Recall that the frequency of
ultrasound is higher than the
upper threshold of human
hearing (20 000 Hz) because
the ear cannot detect these
very high frequencies.
• compression
• wavelength
• frequency
• rarefaction
• amplitude.
Targets for
Improvement
Recognise that ultrasound can
be used in medicine for
diagnostic purposes:
• to look inside people by
scanning the body
• to measure the speed of
blood flow in the body
(candidates are not expected
to describe the Doppler
effect).
Recognise that ultrasound can
be used in medicine for noninvasive therapeutic purposes
such as to break down kidney
and other stones.
Explain how ultrasound is used
in:
• body scans (reflections from
different layers returning at
different times from different
depths)
• breaking down
accumulations in the body
such as kidney stones.
Explain the reasons for using
ultrasound rather than X-rays
for certain scans:
• able to produce images of
soft tissue
• does not damage living cells.
P4d Activities
1. Label the feature of a longitudinal wave below to include:




Wavelength
Amplitude
Rarefaction
Compression
2. Draw and label a transverse wave in the box below to include:
wavelength; amplitude; trough; crest/peak and rest position.
3. What is ultrasound? (you must refer to its frequency in your
answer)
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
4. Give three uses of ultrasound.
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
5. Explain how ultrasound is used for fetal scanning.
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
6. Why is ultrasound used for fetal scanning and not x-rays?
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
Module P4: Radiation for Life
P4e: What is radioactivity?
Nuclear radiation is often misunderstood and frightening. Many people will come across nuclear radiations in everyday life. This
item explores the properties and uses of nuclear radiation.
GRADE G - D
GRADE C
Recognise that the
radioactivity or activity of an
object is measured by the
number of nuclear decays
emitted per second.
Describe radioactive
substances as decaying
naturally and giving out
nuclear radiation in the form of
alpha, beta and gamma.
Understand that radioactivity
decreases with time.
Explain and use the concept
of half-life.
Recall that nuclear radiation
ionises materials.
Interpret graphical data of
radioactive decay to include a
qualitative description of halflife.
Explain ionisation in terms of:
• removal of electrons from
particles
• gain of electrons by particles.
GRADE B – A*
Interpret graphical or
numerical data of radioactive
decay to include calculation
of half-life.
Explain why alpha particles are
such good ionisers.
Targets for
Improvement
Recall that radiation comes
from the nucleus of the atom.
Describe radioactivity as
coming from the nucleus of an
atom that is unstable.
Recall that an alpha particle is
a helium nucleus.
Recall that a beta particle is a
fast moving electron.
Describe what happens to a
nucleus when an alpha
particle is emitted:
• mass number decreases by 4
• nucleus has two fewer
neutrons
• nucleus has two fewer
protons
• atomic number decreases
by 2
• new element formed.
Describe what happens to a
nucleus when a beta particle is
emitted:
• mass number is unchanged
• nucleus has one less neutron
• nucleus has one more proton
• atomic number increases by
one
• new element formed.
Construct and balance
nuclear equations in terms of
mass numbers and atomic
numbers to represent alpha
and beta decay.
P4e Activities
1. For each of the statements below, decide if they are true or
false Re-write any false statements to make them true.
1.
2.
3.
4.
5.
6.
Statement
Radioactivity is measured by the number of
nuclear decays emitted per second.
Radioactivity increases with time.
An alpha particle is the same as a helium
atom.
Nuclear radiation ionises materials.
Beta particles are fast moving high energy
electrons.
Radiation comes from the electrons of the
atom that is stable.
True
False
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
……………………………………………………………………………………
2. (a) Define ionisation.
……………………………………………………………………………………
(b) How does a material become positively ionised?
……………………………………………………………………………………
(c) How does a material become negatively ionised?
……………………………………………………………………………………
3. What is the definition of half-life?
……………………………………………………………………………………
……………………………………………………………………………………
4. Work out the half-life of a radioactive isotope that…
(a) Starts with an activity of 20 Bq and four minutes later has a
radioactivity of 5 Bq.
……………………………………………………………………………………
(b) Starts with an activity of 64 Bq and 6 seconds later has a
radioactivity of 4 Bq.
……………………………………………………………………………………
(c) Starts with an activity of 800 Bq and nine million years later has
a radioactivity of 100 Bq.
……………………………………………………………………………………
5. The table below shows the change in mass number and atomic
number of an atom for different types of radioactive decay.
Changes in atomic number
Changes in mass number
A
-1
0
B
-2
-4
C
0
0
D
+1
0
Write down the letter which shows how the atomic number and
mass number change for the following:
(a) emission of an alpha particle ………………………………………...
(b) emission of an beta particle ………………..………………………...
(c) emission of an gamma particle ……………………………………...
6. Complete the following nuclear equations and circle if it is
alpha or beta decay:
𝟐𝟑𝟐
𝟗𝟎𝑻𝒉
→ 𝟒𝟐𝑯𝒆 +
𝟐𝟒𝟏
𝟗𝟒𝑷𝒖
→
𝟏𝟒
𝟔𝑪
→
𝟎
−𝟏𝒆
𝑹𝒂
alpha / beta
+ 𝟐𝟒𝟏
𝟗𝟓𝑨𝒎
alpha / beta
+
alpha / beta
Module P4: Radiation for Life
P4f: Radioisotopes
The uses of radioisotopes include tracers, smoke alarms, cancer treatment and radioactive dating. This item illustrates the use of
contemporary scientific and technological developments and their benefits, drawback and risks.
GRADE G - D
Understand why background
radiation can vary.
Recall that background
radiation mainly comes from
rocks and cosmic rays.
Recall industrial examples of
the use of tracers:
• to track dispersal of waste
• to find leaks/blockages in
underground pipes
• to find the route of
underground pipes.
GRADE C
GRADE B – A*
Recall that some background
radiation comes from waste
products and man-made
sources e.g. waste from:
• industry
• hospitals.
Evaluate the relative
significance of sources of
background radiation.
Describe how tracers are used
in industry:
• radioactive material put into
pipe
• progress tracked with
detector above
ground/outside pipe
• leak/blockage shown by
reduction/no radioactivity
after the point of blockage.
Explain why gamma radiation
is used as an industrial tracer.
Targets for
Improvement
Recall that alpha sources are
used in some smoke detectors.
Explain how a smoke detector
with an alpha source works:
• smoke particles hit by alpha
radiation
• less ionisation of air particles
• current is reduced causing
alarm to sound.
Recall that radioactivity can
be used to date rocks.
Explain how the radioactive
dating of rocks depends on
the calculation of the
uranium/lead ratio.
Explain how measurements of
the activity of radioactive
carbon can lead to an
approximate age for different
materials:
Recall that measurements from
radioactive carbon can be
• the amount of Carbon-14 in
used to find the date of old
the air has not changed for
materials.
thousands of years
• when an object dies (e.g.
wood) gaseous exchange with
the air stops
• as the Carbon-14 in the
wood decays the activity of
the sample decreases
• the ratio of current activity
from living matter to the
activity of the sample is used to
calculate the age within
known limits.
P4f Activities
1. Outline the different sources of background radiation:
Natural
Man-made
2. Alpha sources are used in some smoke detectors. Outline how
smoke alarms work using the keywords smoke particles, ionisation
and current in your answer.
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3. Draw and annotate a diagram to show how gamma radiation
can be used as an industrial tracer to detect leaks/blockages in
pipes.
4. Radioactivity can be used to date rocks and depends on the
calculation of the ratio between two elements. What are they?
……………………………… and ………………………………
5. Radioactive carbon can be used to find the date of old
materials.
(a) Circle the radioisotope of carbon used in dating materials.
12
6𝐶
13
6𝐶
14
6𝐶
15
6𝐶
(b) The radioisotope used in carbon dating has a half-life of 5700
years. What fraction will remain after (i) 11 400 years (ii) 17 100
years?
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(c) Outline how carbon dating works.
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(d) What are the assumptions made?
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Module P4: Radiation for Life
P4g: Treatment
The concept of medical physics runs through this item. Radiations are important medicinal tools. This item looks at the use of
radiations and the precautions taken to reduce the potential risks.
GRADE G - D
Describe some similarities and
differences between X-rays
and gamma rays:
• both are ionising
electromagnetic waves
• have similar wavelengths
• are produced in different
ways.
GRADE C
Recall that materials absorb
some ionising radiation.
Understand how the image
produced by the absorption
of X-rays depends on the
thickness and density of the
absorbing materials.
GRADE B – A*
Explain how:
• gamma rays are given out:
from the nucleus of certain
radioactive materials
• X-rays are made: by firing high
speed electrons at metal
targets
• X-rays are easier to control
than gamma rays.
Recall that medical
radioisotopes are produced
by placing materials into a
nuclear reactor.
Describe how materials can
become radioactive as a
result of absorbing extra
neutrons.
Targets for
Improvement
Describe uses of nuclear
radiation in medicine, to
include:
• diagnosis
• treatment of cancer using
gamma rays
• sterilisation of equipment.
Recall that only beta and
gamma radiation can pass
through skin.
Recall that nuclear radiation
can damage cells.
Describe the role of a
radiographer and the safety
precautions they must take.
Explain why gamma (and
sometimes beta) emitters can
be used as tracers in the
body.
Understand why medical
tracers should not remain
active in the body for long
periods.
Explain how radioactive sources
are used in medicine:
1. to treat cancer:
• gamma rays focused on
tumour
• wide beam used
• rotated round the patient with
tumour at centre
• limiting damage to noncancerous tissue.
2. as a tracer:
• beta or gamma emitter with a
short half life
•drunk/eaten/ingested/injected
into the body
• allowed to spread through the
body
• followed on the outside by a
radiation detector.
P4g Activities
1. Give two similarities between X-rays and gamma rays:
…………………………………………………………………………………..
…………………………………………………………………………………..
2. One difference between X-rays and gamma rays is how they
are produced. Explain how they are both produced:
X-rays…………………………………………………………………………..
…………………………………………………………………………………..
Gamma………………………………………………………………………..
…………………………………………………………………………………..
3. How do you make a material become radioactive?
…………………………………………………………………………………..
…………………………………………………………………………………..
4. Match up the keywords to their definitions:
Ionisation
The decomposition of the nuclei of
unstable isotopes.
Radiation
The name given to the person in hospitals
who takes x-rays and uses radiation.
Radioactivity
Where an atom loses or gains
electrons.
Radiographer
The units that radioactivity are
measured in.
Becquerels (Bq)
The name given to the energy and
particles that are released during decay.
5. Give three safety precautions when using radioactive materials.
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6. Why can gamma (and sometimes beta) but not alpha be used
as a tracer in the body? How does a tracer work in the body?
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7. Draw and annotate a diagram to show how gamma radiation
can be used in medicine to treat cancer.
8. Give one other use of gamma radiation in medicine?
……………………………………………………………………………………
Module P4: Radiation for Life
P4h: Fission and Fusion
This item deals with work on the processes of nuclear fission and fusion. Nuclear fission is a major source of energy and can be
used to produce electricity. Oil and gas will become less important as supplies decrease and alternative forms of energy will be
needed. This item explains the process of nuclear fission and how the energy produced can be harnessed to produce
electricity. The prospect of harnessing nuclear fusion for power generation is also considered.
GRADE G - D
Recognise that nuclear power
stations use uranium as a fuel.
Describe the main stages in
the production of electricity:
• source of energy
• used to produce steam
• used to produce electricity.
GRADE C
Describe how domestic
electricity is generated at a
nuclear power station:
• nuclear reaction
• producing heat
• heating water to produce
steam
• spinning a turbine
• driving a generator.
GRADE B – A*
Describe what happens to
allow uranium to release
energy:
• uranium nucleus hit by
neutron
• causes nucleus to split
• energy released
• more neutrons released.
Targets for
Improvement
Describe the process that gives Understand how the decay of
out energy in a nuclear reactor uranium starts a chain
as nuclear fission, and that it is
reaction.
kept under control.
Describe a nuclear bomb as a
Recall that nuclear fission
chain reaction that has gone
produces radioactive waste.
out of control.
Explain what is meant by a
chain reaction:
• when each uranium nucleus
splits more than one neutron is
given out
• these neutrons can cause
further uranium nuclei to split.
Explain how scientists stop
nuclear reactions going out of
control:
• rods placed in the reactor
• to absorb some of the
neutrons
• allowing enough neutrons to
remain to keep the process
operating.
Describe the difference
between fission and fusion:
• fission is the splitting of nuclei
• fusion is the joining of nuclei.
Describe how nuclear fusion
releases energy:
• fusion happens when two
nuclei join together
• fusion produces large
amounts of heat energy
• fusion happens at extremely
high temperatures.
Describe why fusion for power
generation is difficult:
• requires extremely high
Explain how different isotopes
of hydrogen can undergo
fusion to form helium:
1
1𝐻
+ 21𝐻 → 32𝐻𝑒
Understand the conditions
needed for fusion to take
place, to include:
• in stars, fusion happens under
temperatures
• high temperatures have to
be safely managed.
Understand why fusion power
research is carried out as an
international joint venture.
extremely high temperatures
and pressures
• fusion bombs are started with
a fission reaction which creates
exceptionally high
temperatures
• for power generation
exceptionally high
temperatures and/or pressures
are required and this
combination offers (to date)
safety and practical
challenges.
Recall that one group of
scientists have claimed to
successfully achieve ‘cold
fusion’.
Explain why the claims are
disputed: other scientists could
not repeat their findings.
Explain why the ‘cold fusion’
experiments and data have
been shared between
scientists.
Explain why ‘cold fusion’ is still
not accepted as a realistic
method of energy production.
P4h Activities
1. Label and annotate each part of the diagram below to show
how nuclear fuel can be used in the production of electricity.
2. Annotate the diagram below to show what happens in nuclear
fission.
3. What is meant by the term “chain reaction” and why can this be
potentially dangerous?
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4. How do scientists stop nuclear reactions going out of control?
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5. What is the difference between fission and fusion?
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6. How does nuclear fusion release energy? What conditions are
needed?
1
1𝐻
+ 21𝐻 → 32𝐻𝑒
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These are six mark questions. You will also be assessed on the quality of
your written communication (spelling, punctuation and grammar).
The 6 mark question template
Science – write down
the key words/points you
will use:
(you can photocopy this page and use it to practice each of the questions)
Structure –
Write a brief plan of the
order you will write your
points :
1.
2.
3.
4.
5.
6.
6 marks? No
problem! Just
remember
SSS...
Now you are ready to
write your answer!
SPAG (spelling,
punctuation and
grammar).
Make sure you have
used full stops, commas,
and other punctuation
correctly.