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AQA GCSE Physics
Paper 1 Knowledge
Name: _______________________________
Energy
Electricity
Particle Model of Matter
Atomic Structure
BOLD = Higher Tier Only
(P) = Physics Only
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Week 1 Questions
No. Question Test 1 Test 2 Test 3
1 What is a system?
2 What happens to the energy in a system when the system
changes?
3 What are the energy store changes when a ball is thrown
upwards?
4 What are the energy store changes when a moving object hits an
obstacle?
5 What are the energy store changes when an object is
accelerated by a constant force?
6 What are the energy store changes when a vehicle applies its
brakes to slow down?
7 What are the energy store changes when water is boiled in an
electric kettle?
8 If 500 J of electrical energy is used by a kettle to heat some
water, how much heat energy will the water have gained?
9 What store of energy is associated with moving objects?
10 What is the word equation for kinetic energy?
11 What is the symbol equation for kinetic energy?
12 What are the units of kinetic energy?
13 What store of energy is associated with a stretched
spring?
14 What is the word equation for elastic potential energy?
15 What is the symbol equation for elastic potential energy?
16 What are the units of elastic potential energy?
17 What store of energy is associated with the height of an
object above ground level?
18 What is the word equation for gravitational potential
energy?
19 What is the symbol equation for gravitational potential
energy?
20 What are the units of gravitational potential energy?
TOTAL
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Week 1 Answers
No. Answer
1 A system is an object or group of objects.
2 The way the energy is stored changes.
3
The person throwing the ball supplies kinetic energy which
causes the ball to rise. The ball slows down as it rises, which
causes the store of kinetic energy to transfer to gravitational
potential energy.
4
The moving object has a store of kinetic energy, which is
transferred to other stores when it hits the obstacle and suddenly
stops. Some of these stores include elastic potential energy in
squashing objects and vibrational energy as a sound is emitted.
5
When a constant force is applied across a distance, work is done
on the object. This work is transferred to a store of kinetic
energy in the object, causing it to move.
6
A moving vehicle has a store of kinetic energy, and when the
brakes are applied there is a large amount of friction. As this
happens, heat energy is released.
7
The kettle transfers a store of electrical energy to heat
energy, which is transferred to the water to heat it up as the
molecules have more vibrational energy.
8 500 J
9 Kinetic energy
10 kinetic energy = 0.5 x mass x (speed)2
11 Ek = 1/2 m v2
12 Joules, J
13 Elastic potential energy
14 elastic potential energy = 0.5 x spring constant x
(extension)2
15 Ee = 1/2 k e2
16 Joules, J
17 Gravitational potential energy
18 g p e = mass x gravitational field strength x height
19 Ep = m g h
20 Joules, J
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Week 2 Questions
No. Question Test 1 Test 2 Test 3
21 What is the store of energy that is associated with
temperature changes?
22 What is the word equation for the change in thermal
energy?
23 What is the symbol equation for the change in thermal
energy?
24 What is the unit of specific heat capacity?
25 What is the specific heat capacity of a substance?
26 In the specific heat capacity required practical, why is it
important to insulate the block?
27 What is the definition of power?
28 What is the word equation for power?
29 What is the symbol equation for power?
30 What is the unit of power?
31 What does 1 Watt mean?
32
Compare the power of two electric motors that both lift the same
weight through the same height, but one does it faster than the
other.
33 What is the principle of conservation of energy?
34 When there are energy transfers in a closed system, what
happens to the total energy of the system?
35 What does it mean when we say that energy is "wasted"?
36 Give some examples of how to reduce unwanted energy
transfers.
37 What does thermal conductivity mean?
38 What factors affect the rate of cooling of a building?
39 In the insulation required practical, what is the independent
variable?
40 What does the efficiency of an energy transfer tell us?
TOTAL
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Week 2 Answers
No. Answer
21 Thermal energy
22 change in thermal energy = mass x specific heat capacity x
temperature change
23 ∆E = m c ∆θ
24 J/kg °C
25 It is the amount of energy required to raise the temperature
of 1 kg of the substance by 1 °C.
26 So that all of the thermal energy transferred to the block is
used to increase its temperature and is not dissipated to the
surroundings.
27 Power is defined as the rate at which energy is transferred
or the rate at which work is done.
28 power = energy transferred ÷ time, power = work done ÷
time
29 P = E ÷ t, P = W ÷ t
30 Watts, W
31 An energy transfer of 1 Joule per second.
32 The one which does it faster has the greater power.
33 Energy cannot be created or destroyed, it can only be
transferred usefully, stored or dissipated.
34 There is no net change to the total energy.
35 In all system changes energy is dissipated, so that it is
stored in less useful ways - such as thermal energy.
36 Thermal insulation, lubrication…
37 The higher the thermal conductivity of a material the higher
the rate of energy transfer by conduction across the material.
38 The thickness and thermal conductivity of its walls.
39 The type and thickness of insulating materials
40 How much of the total input energy is transferred
usefully
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Week 3 Questions
No. Question Test 1 Test 2 Test 3
41 What is the word equation for efficiency of an energy
transfer?
42 What is the word equation for efficiency of a power
output?
43 How can the efficiency of an energy transfer be
increased?
44 What is the definition of a renewable energy resource?
45 What are some examples of renewable energy resources?
46 What is the definition of non-renewable energy?
47 What are some examples of non-renewable energy resources?
48 What are some examples of uses of energy resources?
49 Why are some energy resources more reliable than others?
50 What environmental impact do some resources cause?
51 Although we know that these environmental issues arise, why
can we not always deal with them?
TOTAL
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Week 3 Answers
No. Answer
41 efficiency = useful output energy transfer ÷ total input
energy transfer
42 efficiency = useful power output ÷ total power input
43 By using lubrication or insulation
44 It is one that can be replenished as it is used.
45 Biofuel, wind, hydroelectricity, geothermal, tidal, solar,
wave
46 It is one that cannot be replenished as it takes too
long.
47 Fossil fuels (coal, oil, natural gas), nuclear
48 Transport, electricity generation, heating.
49
Some resources rely on the weather (such as solar and wind
power) which may not always be favourable, but some resources are
always accessible such as fossil fuels.
50 Burning fossil fuels and biofuel release CO2 into the
atmosphere which contributes to global warming.
51 There may be political, social, ethical or economic
considerations.
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Week 4 Questions
No. Question Test 1 Test 2 Test 3
52 Draw the circuit symbols for a variable resistor and a
thermistor
53 Draw a series circuit containing a cell and a bulb.
54 Draw a parallel circuit containing a cell and two bulbs.
55 What is needed for electrical charge to flow through a closed
circuit?
56 What is electric current?
57 In most circuits, what is the charge that flows to carry the
current.
58 What is the word equation for flow of charge?
59 What is the symbol equation for flow of charge?
60 What is the unit of charge?
61 What is the unit of current?
62 At any point in a single closed loop, the current…
63 The current through any component depends on…
64 What is the definition of resistance?
65 What is the unit of resistance?
66 What is the alternative term for potential difference, that
means the same thing?
67 What is the word equation for potential difference?
68 What is the symbol equation for potential difference?
69 What is the unit of potential difference?
70 What is a series circuit?
71 What is a parallel circuit?
TOTAL
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Week 4 Answers
No. Answer
52
53
54
55 A source of potential difference.
56 The rate of flow of electrical charge.
57 Electrons
58 charge flow = current x time
59 Q = I t
60 Coulombs, C
61 Amperes, A
62 is the same.
63 the resistance ( R ) of the component and the potential
difference (V) across it.
64 The amount that a component or circuit opposes the flow of
current.
65 Ohms, Ω
66 Voltage
67 potential difference = current x resistance
68 V = I R
69 Volts, V
70 A circuit where all of the components are connected in one
loop.
71 A circuit where there is more than one loop of
components.
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Week 5 Questions
No. Question Test 1 Test 2 Test 3
72 What piece of equipment is used to measure current?
73 How should it be connected into a circuit?
74 What piece of equipment is used to measure potential
difference?
75 How should it be connected into a circuit?
76 In the required practical on measuring resistance, what is
the dependent variable?
77 For some resistors, the resistance always remains constant.
In others, it can change as…
78 At a constant temperature, the current through an ohmic
conductor is…
79 What does the I-V graph for an ohmic conductor look like?
80 What does it mean that a component is "ohmic"?
81 What happens to the resistance of a filament lamp as
temperature of the filament increases?
82 What does the I-V graph for a filament lamp look like?
83 Describe the current flow through a diode.
84 What does the I-V graph for a diode look like?
85 What is a thermistor?
86 When would a thermistor be useful?
87 What is an LDR?
88 When would an LDR be useful?
89 To measure the resistance of a component, what measurements
should be made?
90 Draw a circuit to show how the resistance of a resistor could
be measured?
91 In the required practical on investigating I-V
characteristics of components, what is the independent
variable?
TOTAL
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Week 5 Answers
No. Answer
72 Ammeter
73 In series
74 Voltmeter
75 In parallel with the component that you are measuring the
potential difference across.
76 Resistance
77 the current changes.
78 directly proportional to the potential difference across the
resistor.
79
80 Resistance remains constant as current changes.
81 It increases.
82
83 It can only flow in one direction. There is a very high
resistance in the reverse direction.
84
85 A resistor that decreases its resistance as temperature
increases.
86 Thermostats
87 A Light Dependent Resistor decreases its resistance as light
intensity increases.
88 Light sensors, e.g. to switch on lights when it gets dark
89 Measurements of the current through the component and the
potential difference across it.
90
91 The component that is being measured.
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Week 6 Questions
No. Question Test 1 Test 2 Test 3
92 In a series circuit, what can be said about the current,
potential difference and resistance?
93 What is the equation for the total resistance of a series
circuit?
94 In the branches of a parallel circuit, what can be said about
the current, potential difference and resistance?
95 Why does adding resistors in parallel decrease the total
resistance?
96 What is DC?
97 What is AC?
98 What the frequency of the AC domestic electricity supply in
the UK?
99 What is the potential difference of the domestic electricity
supply in the UK?
100 How many wire-cores make up the wire of most electrical
appliances?
101 Why is each wire wrapped in a plastic coating?
102 What does the colour coding on each wire identify it as?
103 What does the live wire do, and what is its potential
difference?
104 What does the neutral wire do, and what is its potential
difference?
105 What does the earth wire do, and what is its potential
difference?
106 When is a live wire dangerous?
107 Why would it be dangerous to provide a connection between
the live wire and the earth wire?
108 What is the power transfer in a circuit related to?
109 What two word equations relate power, potential difference,
current and resistance?
110 What two symbol equations relate power, potential
difference, current and resistance?
111 What is the unit of power?
TOTAL
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Week 6 Answers
No. Answer
92
The current is the same through each component. The total
potential difference of the power supply is shared between the
components. The total resistance is the sum of the individual
resistances.
93 Rtot = R1 + R2 …
94
The total current splits between the "branches" of the parallel
circuit. The potential difference across each branch is the same.
The total resistance of two resistors in parallel is less than the
resistance of the lowest of the resistors.
95 There are more routes for electrons to take between the
branches, so it is easier for current to flow.
96 Direct Current (DC) is when current always flows in one
direction. It is the current found in circuits powered by a cell or
battery.
97 Alternating Current (AC) is when the direction of current
flow rapidly changes, giving an alternating potential difference.
It is how mains electricity is supplied in the UK.
98 50 Hz
99 230 V
100 3
101 As a safety feature. The plastic acts as an insulator from
the electricity in case anyone were to touch it. The colours also
indicate which wire is inside it.
102 Brown - live wire. Blue - neutral wire. Green and yellow
stripes - earth wire.
103 It carries the alternating potential difference from the
power supply. The potential difference between the live wire and
earth is around 230 V.
104 It completes the circuit and is close to earth potential (0
V).
105 It is a safety wire to stop the casing of the appliance from
becoming live, so is at 0 V and only carries a current if there is
a fault.
106 They are always dangerous when a current is flowing, but it
may still be dangerous even if a switch is open.
107 It could cause a spark.
108 The potential difference across the circuit, the current
through it and the energy changes over time.
109 power = potential difference x current, power = (current)2 x
resistance
110 P = V I , P = I2R
111 Watts, W
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Week 7 Questions
No. Question Test 1 Test 2 Test 3
112 What does the amount of energy an appliance transfers depend
on?
113 What does work have to do with electric circuits?
114 Which two word equations relate energy transferred, power,
time, charge and potential difference?
115 What two symbol equations relate energy transferred, power,
time, charge and potential difference?
116 What are the units of energy?
117 What is the National Grid?
118 What is a transformer?
119 What does a step-up transformer do?
120 What does a step-down transformer do?
121 (P) Why is static electricity called "static"?
122 (P) What type of charge do electrons have?
123(P) How is static electricity produced?
124 (P) What happens when electrically charged objects are
brought close together?
125 (P) What happens to two objects with the same type of
charge?
126 (P) What happens to two objects with different types of
charge?
127 (P) What is an electric field?
128 (P) What happens if another charged object is placed in the
field?
129 (P) What does the electric field pattern look like for a
positive charge near a negative charge?
TOTAL
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Week 7 Answers
No. Answer
112 The power of the appliance and how long it is switched on
for.
113 Work is done when charge flows in a circuit.
114 energy transferred = power x time, energy transferred =
charge x potential difference
115 E = P t E = Q V
116 Joules, J
117 The National Grid is a system of cables and transformers
linking power stations to consumers.
118 A device which alters the potential difference and current
of electricity in the cables.
119 They are used to increase the potential difference from the
power station to the transmission cables to reduce energy loss in
transportation.
120 They are used to decrease, to a much lower value, the
potential difference for safe domestic use.
121 It is related to "static" (or still) electrons which build
up on materials.
122 Negative charge
123
When certain insulating materials are rubbed against each other
they become electrically charged. Negatively charged electrons are
rubbed off one material and on to the other. The material that
gains electrons becomes negatively charged. The material that loses
electrons is left with an equal positive charge.
124 When two electrically charged objects are brought close
together, they exert a force on each other.
125 They repel each other.
126 They are attracted to each other.
127
A charged object creates an electric field around itself. The
electric field is strongest close to the charged object. The
further away from the charged object, the weaker the field.
128 A second charged object placed in the field experiences a
force. The force gets stronger as the distance between the objects
decreases.
129
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Week 8 Questions
No. Question Test 1 Test 2 Test 3
130 What is the definition of density?
131 What is the word equation for density?
132 What is the symbol equation for density?
133 What are some common units of density?
134 What is the particle model useful for?
135 Draw a particle diagram for solid, liquid and gas.
136 Describe how to find the volume of a regular solid.
137 Describe how to find the volume of an irregular solid,
including a labelled diagram of the required equipment.
138 What other equipment could be used to measure length, if
required to a more precise value?
139 When is mass conserved?
140 What makes a change of state different to a chemical
change?
141 What is internal energy?
142 How does heating an object change the internal energy?
143 What does the increase in temperature of a system depend
on?
144 What is the word equation that relates the change in thermal
energy of a system to the factors that it depends upon?
145 What is the symbol equation that relates the change in
thermal energy of a system to the factors that it depends upon?
146 What are the units of specific heat capacity?
147 What is the specific heat capacity of a substance?
148 What is latent heat?
149 What is the specific latent heat of a substance?
TOTAL
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Week 8 Answers
No. Answer
130 The amount of matter in a given volume.
131 density = mass ÷ volume
132 ρ = m/V
133 kg/m3 g/cm3
134
The idea that solids, liquids and gases are all made up of
particles in different arrangements is useful to explain the states
of matter and the differences in their density: solids are denser
than gases as there are more particles in a given volume than gases
have.
135
136 Use a ruler to measure the length, width and height of the
object and use them to find the volume. Place the object on a
balance to find the mass. Find the density by dividing the mass by
the volume.
137
Place the object on a balance to find its mass. Fill a
displacement can with water and let it drip until it no longer
drips. Place the irregular object into the displacement can with a
measuring cylinder under the spout. The volume of water that is
displaced out of the can by the object is the same as the volume of
the object. find the density by dividing the mass by the
volume.
138 A micrometer or a set of Vernier callipers.
139 Always during changes of state; melting, freezing, boiling,
evaporating, condensing and subliming.
140 They are physical changes, so the material will recover its
original properties if the change is reversed.
141 The total kinetic energy and potential energy stored inside
a system by the particles (atoms and molecules) that make up the
system.
142 It increases the energy of the particles that make up the
system to either increase the temperature or cause a change of
state.
143 The mass of the substance, the type of material and the
energy input.
144 change in thermal energy = mass x specific heat capacity x
temperature change
145 ∆E = m c ∆θ
146 J/kg °C
147 The specific heat capacity of a substance is the amount of
energy required to raise the temperature of 1 kg of the substance
by 1 °C.
148 The energy needed for a substance to change state is called
latent heat. When a change of state occurs, the energy supplied
changes the energy stored (internal energy) but not the
temperature.
149 The specific latent heat of a substance is the amount of
energy required to change the state of 1 kg of the substance with
no change in temperature.
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Week 9 Questions
No. Question Test 1 Test 2 Test 3
150 What is the word equation for the energy for a change of
state?
151 What is the symbol equation for the energy for a change of
state?
152 What are the units of specific latent heat?
153 What is the specific latent heat of fusion?
154 What is the specific latent heat of vaporisation?
155
Label this heating graph:
156 What do the molecules of a gas do?
157 A gas can be compressed or expanded by pressure changes.
Where us the net force?
158 What equation relates the pressure and volume of a gas held
at constant temperature?
159 What are the units of pressure?
160 (P) What is work?
161 (P) When work is done on a gas, what happens to the gas?
TOTAL
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Week 9 Answers
No. Answer
150 energy for a change of state = mass × specific latent
heat
151 E = m L
152 J/kg
153 It relates to the change of state from solid to liquid
154 It relates to the change of state from liquid to vapour
155 A - solid, B - melting, C - liquid, D - vaporisation, E -
gas
156 They move with constant random motion. Their kinetic energy
is related to the temperature of the gas.
157 The pressure produces a net force at right angles to the
wall of the gas container (or any surface).
158 pressure x volume = constant, p V = constant
159 Pascals, Pa
160 The transfer of energy by a force.
161 The internal energy increases and it can also cause an
increase in temperature.
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Week 10 Questions
No. Question Test 1 Test 2 Test 3
162 How big is the radius of an atom?
163 What is the basic structure of an atom?
164 Where is most of the mass of the atom?
165 How big is the radius of the nucleus?
166 What are energy levels?
167 What can cause the electron arrangements to change?
168 What is the overall charge of an atom?
169 What is the number of electrons in an atom equal to?
170 All atoms of a particular element have the same…
171 The number of protons in an atom is called the…
172 The number of protons and neutrons in an atom is called
the…
173 How many protons are in atoms of this element?
174 How many neutrons are in atoms of this element?
175 How many electrons are in atoms of this element?
176 What is an isotope?
177 When an atom loses one or more outer electrons, what does it
become?
178 What may lead to a scientific model being changed or
replaced?
179 What did people think about atoms before the discovery of
the electron?
180 What model did the discovery of the electron lead to?
181 What does this model suggest?
TOTAL
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Week 10 Answers
No. Answer
162 About 1 x 10-10 m
163 There is a positively charged nucleus (made up of protons
and neutrons), surrounded by negatively charged electrons.
164 In the nucleus
165 It is less than 1/10,000th of the radius of the atom.
166 The electrons are arranged at different distances from the
nucleus in "energy levels" which are sometimes called "shells".
167
When electromagnetic radiation is absorbed, electrons move
further from the nucleus to a higher energy level. If
electromagnetic radiation is emitted, electrons move closer to the
nucleus to a lower energy level.
168 It has no overall charge, so it is neutral.
169 The number of protons in the nucleus.
170 number of protons.
171 atomic number.
172 mass number.
173 11
174 12
175 11
176 Atoms of the same element with different numbers of
neutrons.
177 A positive ion
178 New experimental evidence
179 They thought that atoms were tiny spheres that could not be
divided.
180 The plum pudding model
181 That an atom is a ball of positive charge with negative
electrons embedded throughout (like plums in the pudding).
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Week 11 Questions
No. Question Test 1 Test 2 Test 3
182 What did the alpha particle scattering experiment show?
183 How did Niels Bohr adapt this model?
184 How did Bohr realise that his suggestions were correct?
185 What did later experiments show that led to the
understanding of protons?
186 What did James Chadwick's experimental work show?
187 What is radioactive decay?
188 What is the "activity" of a radioactive source?
189 What is the unit of activity?
190 What is the count-rate?
191 What are the 4 types of nuclear radiation?
192 What do each of these consist of?
193 What material is required to stop the penetration of each
type?
194 Which type of nuclear radiation is the most and least
ionising?
195 Which type of nuclear radiation has the longest range in
air?
196 State a use of alpha particles:
197 State a use of beta particles:
198 State a use for gamma rays:
199 Why is ionising radiation dangerous?
200 What is the difference between radioactive and
radiation?
201 (P) Why would radioactive sources used as tracers in the
body need a short half-life?
TOTAL
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Week 11 Answers
No. Answer
182 It showed at the mass of an atom was concentrated at the
centre (the nucleus) which was positively charged.
183 He suggested that electrons orbit the nucleus at specific
distances?
184 His theoretical calculations agreed with experimental
observations.
185 Scientists discovered that the positive charge of a nucleus
can be divided into a whole number of smaller particles that each
have the same positive charge.
186 About 20 years after the understanding of the nucleus, he
provided evidence of the existence of neutrons.
187 Some atomic nuclei are unstable, so they give out radiation
as they change to become more stable.
188 It is the rate at which a source of unstable nuclei
decays.
189 Becquerel, Bq
190 It is the number of decays recorded each second by a
detector (such as a Geiger-Muller tube).
191 alpha particles (α), beta particles (β), gamma rays (γ),
neutrons (n).
192
• an alpha particle (α) – this consists of two neutrons and two
protons, it is the same as a helium nucleus • a beta particle (β) –
a high speed electron ejected from the nucleus as a neutron turns
into a proton • a gamma ray (γ) – electromagnetic radiation from
the nucleus • a neutron (n).
193 Alpha - paper, beta - thin aluminium, gamma - thick lead
194 Most ionising - alpha, slightly ionising - beta, not
ionising - gamma.
195 Longest range - gamma, mid range - beta, very short range -
alpha.
196 They are used in smoke alarms, as smoke particles will stop
alpha particles from reaching a detector.
197
Thickness monitoring of paper or aluminium sheets. The beta must
be able to pass through the sheet to be detected and different
amounts will be detected if the sheet is too thin or too thick.
198 They have several uses in medicine; the kill cancer cells,
to sterilise medical equipment and in radioactive tracers.
199 It can damage the DNA in cells which can cause them to
replicate uncontrollably into tumours.
200
Radioactive - substances which emit nuclear radiation are
radioactive. Radiation is the word for the alpha particles, beta
particles and gamma rays that are emitted from radioactive
substances.
201 So that they don't remain radioactive for a long time inside
the body as that would be dangerous.
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Week 12 Questions
No. Question Test 1 Test 2 Test 3
202 (P) Why would radioactive sources used in appliances need a
long half-life?
203 How is an alpha particle represented in a nuclear
equation?
204 How is a beta particle represented in a nuclear
equation?
205 What changes to the nucleus does emission of nuclear
radiation cause?
206 Write an equation for the alpha decay of radon-219.
207 Write an equation for the beta decay of carbon-14.
208 What key word can be used to describe the nature of
radioactive decay?
209 What is the half-life of a radioactive substance?
210 What is the half-life of this substance?
211 What is radioactive contamination?
212 What is irradiation?
213 What precautions should people take when working with
radioactive substances?
214
Why is it important for the findings of studies into the effects
of radiation on humans to be published and shared with other
scientists?
215 (P) Where does background radiation come from?
216 (P) What can affect the level of background radiation or a
person's radiation dose?
217 (P) What is the unit of radiation dose?
218 (P) How many millisieverts (mSv) make up 1 sievert (Sv)?
219 (P) What medical uses are there for nuclear radiation?
220 (P) What is nuclear fission?
221 (P) Spontaneous fission is rare. What must usually first
happen for fission to occur?
222 (P) What happens during nuclear fission?
223 (P) What can happen with the neutrons that are released?
224 (P) Draw a diagram to represent nuclear fission and show how
a chain reaction might happen:
225 (P) What is nuclear fusion?
TOTAL
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Week 12 Answers
No. Answer
202 So that they don’t need to be replaced so regularly.
203
204
205 Changes to the mass and/or charge of the nucleus.
206
207
208 Random
209
The half-life of a radioactive isotope is the time it takes for
the number of nuclei of the isotope in a sample to halve, or the
time it takes for the count rate (or activity) from a sample
containing the isotope to fall to half its initial level.
210 2 days
211
Radioactive contamination is the unwanted presence of materials
containing radioactive atoms on other materials. The hazard from
contamination is due to the decay of the contaminating atoms. The
type of radiation emitted affects the level of hazard.
212 Irradiation is the process of exposing an object to nuclear
radiation. The irradiated object does not become radioactive.
213 Distance, gloves, suits, screens, minimise exposure
time.
214 So that the findings can be checked by peer-review and
shared more widely if important.
215 Natural sources like rocks and cosmic rays from space.
Man-made sources like nuclear weapons testing and nuclear
accidents.
216 Location or occupation
217 Sieverts, Sv
218 1000 millisieverts (mSv) = 1 sievert (Sv)
219 Exploration of internal organs, control or destruction of
unwanted tissue.
220 Nuclear fission is the splitting of a large and unstable
nucleus (e.g. uranium or plutonium).
221 It must absorb a neutron.
222 The nucleus undergoing fission splits into two smaller
nuclei, roughly equal in size, and emits two or three neutrons plus
gamma rays. Energy is released by the fission reaction.
223 They can start a chain reaction.
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224
225 Nuclear fusion is the joining of two light nuclei to form a
heavier nucleus. In this process some of the mass may be converted
into the energy of radiation.
