Cambridge IGCSE™ Physics

Glossary

Terms marked with an * indicate Supplement material. availability able to be used at all times
* average orbital speed ν = 2πr
absolute zero lowest possible temperature: –273°C or 0 K
T
absorber takes in heat or radiation average speed distance moved/time taken

* acceleration change of velocity per unit time background radiation ever-present radiation resulting from
cosmic rays from outer space and radioactive materials in
acceleration of free fall g; for an object near to the
surface of the Earth, this is approximately constant and is rocks, the air, buildings
approximately 9.8 m/s2
balance instrument used for measuring mass
accretion model build up of mass due to gravitational
attraction between smaller particles leading to the battery consists of two or more electric cells
formation of the Solar System
beam (1) many rays of light (2) rectangular-shaped rod
activity the average number of atoms which decay per
second of a sample of radioactive material beta particles β-particles; radiation consisting of
high-speed electrons ( 0 e)
advantages of high-voltage transmission of electricity −1
(i) lower power loss in transmission cables and (ii) lower
currents in cables so thinner/cheaper cables can be used bimetallic strip equal lengths of two different metals
riveted together
air resistance frictional force opposing the motion of a
body moving in air biofuels fuel obtained from plants or animal dung and
sewage
alpha particles α-particles; radiation consisting of helium
ions with a double positive charge (24 He) biogas a mixture of methane and carbon dioxide produced
alternating current a.c.; the direction of current flow from animal and human waste
reverses repeatedly
boiling temperature temperature at which bubbles of
* alternator a.c. generator vapour form in a liquid

ammeter instrument used to measure electric current Brownian motion random motion due to molecular
collisions, experienced for example by smoke particles
ampere A; unit of current
suspended in air
amplitude height of crest (or depth of trough) of a wave,
measured from the undisturbed position of the medium * brushes in a motor or generator; carbon blocks which act
carrying the wave as electrical contacts

* analogue continuously varying bubble chamber a device which uses bubbles in liquid
hydrogen to make the paths of α-, β- and γ-radiation visible
angle of incidence angle between incident ray and the
normal to a surface cathode negatively charged electrode

angle of reflection angle between reflected ray and the cathode rays beams of high-speed electrons
normal to a surface
centimetre 10–2 m
angle of refraction angle between refracted ray and the
normal to a surface centre of gravity the point at which all of an object’s
weight can be considered to be concentrated
anode positively charged electrode
* centripetal force force acting towards the centre which
area of a circle πr2 where r is the radius of the circle keeps a body moving in a circular path

area of a square or rectangle length × breadth * chain reaction a set of nuclear reactions which are
started by a single fission
area of a triangle base × height/2
chemical energy energy stored (for example in food and
* armature coil and core of an electric motor fuel) which can be released by chemical reactions

atom tiny constituent of matter circuit breaker used instead of a fuse to break a circuit
when the current exceeds a certain value
* atomic bomb produces an uncontrolled chain reaction
combined resistance of two resistors in parallel less than
that of either resistor by itself

condensation change of a gas or vapour to a liquid

341

Glossary

conduction flow of thermal energy through matter from diffuse reflection a parallel beam of light is reflected in
places of higher temperature to places of lower temperature many different directions at a rough surface
without movement of the matter as a whole
diffusion cloud chamber a device which makes the paths
conductor material which allows thermal energy or of α-, β- and γ-radiation visible
electrons to flow easily
* digital using discrete values only
constant having the same value
direct current d.c.; electrons flow in one direction only
constant of proportionality the ratio of two variables
which are directly proportional to each other direction of a magnetic field at a point the direction of
the force on the N pole of a magnet at that point
continuous ripples a wave
direction of an electric field at a point the direction of
convection flow of thermal energy through a fluid from the force on a positive charge at that point
places of higher temperature to places of lower temperature
by movement of the fluid itself dispersion separation of white light into its component
colours
convection currents streams of warm moving fluids
displacement distance moved in a stated direction
convector warms air using convection currents
displacement–distance graph graph of the displacement
conventional current direction in which a positive charge from their undisturbed position of the particles
would flow in a circuit transmitting a wave, plotted against their distance from
the source, at a particular instant of time
converging light bends inwards
distance–time graph graph of distance on the vertical axis
* coulomb C; unit of charge plotted against time on the horizontal axis

count-rate counts/second diverging light spreads out

crest of a wave maximum amplitude of a wave dynamic friction frictional force acting on a body moving
at a constant speed
* critical a chain reaction becomes critical when on
average each fission results in another fission event, * dynamo d.c. generator
so that the reaction is sustained
echo reflection of a sound wave
critical angle angle of incidence which produces an angle
of refraction of 90° * eddy currents currents induced in a metal which is in a
changing magnetic field; they cause energy loss in the core
crumple zones front and rear sections of a vehicle, of a transformer
designed to collapse on impact so that kinetic energy is
absorbed gradually * efficiency (useful energy output/energy input) × 100%;
(useful power output/power input) × 100%
cubic centimetre unit used to measure volume (cm3)
effort force required to lift a weight
cubic metre SI unit of volume (m3)
* elastic limit for extensions beyond the elastic limit,
current flow of electric charges; symbol I, measured in a material will not return to its original length when
ampere (A) unloaded; it is permanently stretched and the law of
proportionality no longer applies
* deceleration a negative acceleration; velocity decreases
as time increases * electric current the charge passing a point per unit
time (current I = Q/t where Q is the charge flowing past a
degrees Celsius °C; unit of temperature particular point in time t)

density mass per unit volume electrical energy energy transferred by an electric current

dependent variable quantity whose value depends on that electric cell changes chemical energy into electrical
of another energy

deuterium 12HH; isotope of hydrogen with one proton and * electric field a region of space where an electric charge
one neutron in the nucleus experiences a force due to other charges

diffraction spreading of a wave at the edges of an obstacle

342

Glossary

electric force force between electric charges * fission the break-up of a large nucleus into smaller parts

electrode emitter or collector of electric charges * Fleming’s left-hand (motor) rule when the thumb and
first two fingers of the left hand are held at right angles to
electromagnet temporary magnet produced by passing an each other with the first finger pointing in the direction of
electric current through a coil of wire wound on a soft iron the magnetic field and the second finger in the direction of
the current then the thumb points in the direction of the
core thrust on a wire

electromagnetic induction the production of a p.d. across * Fleming’s right-hand (dynamo) rule used to show the
a conductor when it moves through a magnetic field or is at relative directions of force, field and induced current: when
the thumb and first two fingers of the right hand are held
rest in a changing magnetic field at right angles to each other with the first finger pointing
in the direction of the magnetic field and the thumb in the
electromagnetic radiation radiation resulting from direction of the motion of the wire, then the second finger
electrons in an atom undergoing an energy change; all points in the direction of the induced current
types travel in a vacuum at 3 × 108 m/s (the speed of
light), obey the wave equation and exhibit interference, fluid a liquid or gas

diffraction and polarisation fluorescent emitting light when struck by ultraviolet
radiation or electrons
electromotive force (e.m.f.); the electrical work done by a
source in moving unit charge around a complete circuit focal length distance between the optical centre and the
principal focus of a lens
electron 0 e ; negatively charged elementary particle
−1 focus bring beams to a point

electrostatic induction production of charge on a force a push or pull on a body
conductor when a charge is brought close to it
fossil fuels coal, oil and natural gas formed from the remains
emitter gives out heat or radiation of plants and animals which lived millions of years ago

energy may be stored as kinetic, gravitational potential, * forward bias p.d. connected across a diode such that it
chemical, elastic (strain), nuclear, electrostatic and internal has a low resistance and conducts

(thermal) freezing temperature temperature at which a liquid
changes to a solid
energy density energy/volume
frequency number of complete oscillations per second
energy sources materials and resources from which energy
can be produced friction force which opposes one surface moving, or trying
to move, over another surface
energy transfer change of store or location of energy
fulcrum pivot
equilibrium when there is no resultant force and no
resultant moment on an object fuse a short length of wire which melts when the current in
the circuit exceeds a certain value; it protects the circuit
evaporation loss of vapour from a liquid surface at a from carrying a large current
temperature below the boiling temperature of the liquid
* fusion the union of light nuclei into a heavier one
* exciter supplies d.c. to the electromagnets in the rotor of
an alternator galaxy made up of many billions of stars

expansion increase in size galvanometer an instrument used to detect small currents
and p.d.s
extension change in length of a body being stretched
gamma radiation γ-radiation; high-frequency, very
factors affecting the magnitude of an induced e.m.f. penetrating electromagnetic waves
e.m.f increases with increases of: (i) the speed of motion of
the magnet or coil, (ii) the number of turns on the coil, (iii) gas turbine gas is used to turn the blades of a rotor
the strength of the magnet
Geiger–Müller tube GM tube; detects radiation
field line line which shows the direction of an electric,
magnetic or gravitational field at each point

filament thin coil of wire which can transfer electrical
energy to heat and light (as in a lamp)

343

Glossary

generator electricity-producing machine intensity measure of the magnitude of a quantity such as
sound, light or electric field
geostationary satellite satellite which travels at the
same speed as that at which the Earth rotates and so internal energy energy of the molecules in a body (both
appears to be stationary at a particular point above the potential and kinetic)
Earth’s surface
inversely proportional two variables are inversely
geothermal energy energy obtained from hot rocks below proportional if their product is a constant
the Earth’s surface is used to heat water to steam which is
ionosphere electrically charged particles in the upper
then used to drive a turbine and generate electricity atmosphere

gigametre (Gm) = 109 m = 1 billion metres ionisation process by which an atom or molecule becomes
an ion
* gravitational field a region where the Earth exerts a
force on a body ions charged atoms or molecules which have lost or gained
one or more electrons so that they are no longer neutral
gravitational field strength the force per unit mass

gravitational potential energy energy a body has due to isotopes of an element, are atoms which have the same
its height above the Earth’s surface (mgh) number of protons but different numbers of neutrons in the

half-life of a particular isotope the time taken for half the nucleus
nuclei of that isotope in any sample to decay
joule J; SI unit of energy

hard in magnetic terms, a permanent magnet made from a joulemeter used to measure the electrical energy
material such as steel transferred by an appliance

hazards associated with using mains electricity supply kelvin K; SI unit of temperature; a kelvin has the same size
include damaged insulation, overheated cables, damp as a degree Celsius but 0°C = 273 K
conditions, excess current from overloaded plugs, extension
leads, single and multiple sockets kilogram kg; SI unit for mass

heat exchanger transfers heat from one fluid to another kilometre km; 103 m

hertz units of frequency (cycles per second) kilowatt kW; 103 W

g*aHlauxbybilsemcoovnisntganatw,aHy 0frtohme ratio of the speed at which the kilowatt-hour kWh; the electrical energy used by a
the Earth to its distance from 1 kW appliance in 1 hour; 1 kWh = 1000 J/s × 3600 s
= 3 600 000 J = 3.6 MJ
the Earth; H0 = v/d
kinetic energy Ek; energy a body has due to its motion
hydraulic car brakes oil is used to transmit pressure from (mv2/2)

the brake pedal to the car brakes

hydraulic jack machine in which a liquid is used to transmit laminated layered
pressure and lift an object
law of moments when a body is in equilibrium, the sum of
hydroelectric energy flow of water from a high to a low the clockwise moments about any point equals the sum of
level is used to drive a water turbine connected to an
the anticlockwise moments about the same point
electricity generator
law of reflection the angle of incidence is equal to the
image likeness of an object angle of reflection

* impulse force × time for which force acts length greatest dimension of an object; SI unit is the
metre (m)
independent variable quantity whose value does not
depend on that of another light-dependent resistor LDR; semiconductor device
in which the electrical resistance decreases when the
induction motor a.c. motor
intensity of light falling on it increases

infrared radiation electromagnetic waves emitted by hot, * light emitting diode LED; semiconductor device which
but not glowing, bodies emits light when it is forward biased but not when it is

insulator material which does not allow thermal energy or reverse biased
electrons to flow easily

344

Glossary

light-year used to measure astronomical distances; the microwaves radio waves with a wavelength of a few cm
distance travelled in (the vacuum of) space by light in one year
Milky Way the spiral galaxy to which our Solar System
* limit of proportionality the point at which the load- belongs. The Sun is a star in this galaxy and other stars
extension graph becomes non-linear that make up this galaxy are much further away from the
Earth than the Sun is from the Earth
limits of audibility the approximate range of frequencies
audible to humans, 20 Hz to 20 000 Hz millimetre 10–3 m

* linear conductor conductor which obeys Ohm’s law * moderator graphite core of a nuclear reactor which slows
down fission neutrons
linearly values lie along a line
molecule combination of atoms
line of force see field line
moment of a force moment = force × perpendicular
live wire connected to a high p.d. distance from pivot

load weight * momentum mass × velocity

longitudinal wave direction of vibration of particles of the * monochromatic single colour (frequency) of light
transmitting medium is parallel to the direction of travel of
the wave * motor rule see Fleming’s left-hand rule

loudspeaker converts an electric current into a sound wave multimeter an instrument which can be used to measure
a.c or d.c. currents and voltages and also resistances
luminous object which makes its own light
multiplying factor number of times a force is increased,
magnetic field a region of space where a magnet experiences for example in a hydraulic system
a force due to other magnets or an electric current
musical notes produced by regular vibrations
magnetic force force between magnets
mutual induction occurs when a changing current in one
magnetic materials materials that can be magnetised by a coil produces a changing current in a nearby coil as a result
magnet; in their unmagnetised state they are attracted by of electromagnetic induction
a magnet
nanometre 10−9 m
mass a measure of the quantity of matter in an object at
rest relative to an observer National Grid network of electricity transmission lines

* mass defect mass lost in a reaction; it can be large in negative charges repel other negative charges, but
nuclear reactions such as fission or fusion and become a negative charges attract positive charges
source of energy (E = mc2)
neutral equilibrium occurs when a body stays in its new
mass number A; number of protons and neutrons (nucleons) position when slightly displaced and then released
in the nucleus of an atom
neutral point point at which magnetic fields cancel
mechanical waves to and fro vibration of the particles of a
transmitting medium neutral wire connected to earth

* medical ultrasound imaging technique used to image neutron uncharged particle found in the nucleus of an atom
internal organs of the body using the reflection of (except that of hydrogen)
ultrasonic pulses
newton SI unit of force; N
megawatt MW; 106 W
Newton’s first law of motion a body stays at rest, or if
melting temperature temperature at which a solid changes moving continues to move with uniform velocity, unless an
to a liquid external force makes it behave differently

meniscus curved liquid surface * Newton’s second law of motion
force = mass × acceleration
metre SI unit for length (m)
noise produced by irregular vibrations
micrometre µm; 10–6 m
non-luminous object which does not make its own light;
microphone converts sound waves to an electric current it may reflect light from a luminous source

345

Glossary

non-magnetic materials materials that cannot be polar near the north or south pole of the Earth
magnetised and are not attracted by a magnet
positive charges repel other positive charges, but positive
non-ohmic device which does not obey Ohm’s law charges attract negative charges

non-renewable cannot be replaced when used up potential difference p.d.; the work done by a unit charge
passing through a component
normal line which is perpendicular to a surface
potential divider variable resistor connected so that the
nuclear energy energy derived from nuclei p.d. applied to a device can be changed

nuclear fuels radioactive materials such as uranium, used potential energy energy a body has because of its position
in the core of a nuclear reactor to produce heat or condition (mgh)

nucleon proton or neutron potentiometer resistor whose resistance can be varied

nucleon number A;  number of protons and neutrons in the power the work done per unit time and the energy
nucleus transferred per unit time

nucleus dense core of an atom containing protons and powers of ten way of writing numbers; index gives number
neutrons of times number must be multiplied by 10

nuclide atom of an element characterised by the mass pressure the force per unit area
number A and the proton number Z
primary main, most important
octave notes are an octave apart if the frequency of one
note is twice that of the other principal axis line through the optical centre of a lens at
right angles to the lens
ohm Ω; unit of resistance
principal focus (focal point) point on the principal axis
* ohmic conductor conductor which obeys Ohm’s law of a lens to which light rays parallel to the principal axis
converge, or appear to diverge from
Ohm’s law the current through a metallic conductor is
directly proportional to the p.d. across its ends if the principle of conservation of energy energy cannot be
temperature and other conditions are constant created or destroyed; it is always conserved

optical centre centre of a lens progressive wave travelling wave carrying energy from one
place to another
orbit curved path, such as that taken by a moon around
a planet proportional two variables are proportional if their ratio is
a constant
parallel lines with the same direction
proton positively charged particle found in the nucleus of
parallel circuit components are connected side by side an atom
and the current splits into alternative paths and then
recombines; current from the source is larger than the proton number Z; number of protons in the nucleus
current in each branch
pulse a few cycles of a wave
parallelogram law if two forces acting at a point are
represented in size and direction by the sides of a pumped storage electricity generated at off-peak periods
parallelogram drawn from the point, their resultant is is used to pump water from a low-level reservoir to a high-
represented in size and direction by the diagonal of the level one
parallelogram drawn from the point
quality or timbre of a sound is determined by the number
pascal Pa; SI unit of pressure 1 Pa = 1 N/m2 and strength of the overtones present

period time for one complete oscillation (1/frequency) radar system which enables the position of a distant object
to be found by the use of microwaves directed at and
permanent magnets made of steel, retain their magnetism reflected from the object

perpendicular at 90° radial along a radius

phase vibrating particles transmitting a wave are in phase radiant emits radiation
if they are moving in the same direction and have the same
displacement; if this is not the case, they are out of phase radiation transfer of thermal energy from one place to
another by electromagnetic waves
pitch frequency of a sound wave

346

Glossary

radio waves electromagnetic waves with the longest * reverse bias p.d. connected across a diode such that it
wavelength has a high resistance and does not conduct

radioactive material which emits α-, β- or γ-radiation rheostat variable resistor connected so that the current in
a circuit can be changed
radioactive decay the emission of α-, β- or γ-radiation
from unstable nuclei right angle 90°

radioisotope isotope of an element which is radioactive right-hand grip rule if the fingers of the right hand grip a
solenoid in the direction of the conventional current, the
radionuclide see radioisotope thumb points to the N pole

radiotherapy use of ionising radiation to treat cancer right-hand screw rule if a right-handed screw moves
forwards in the direction of the conventional current, the
random irregular, erratic or haphazard direction of rotation of the screw gives the direction of the
magnetic field
range spread of values
rotor blades or electromagnets on a rotating shaft
ratemeter instrument which counts the number of current
pulses/second (often used with a GM tube) * scalar a quantity which has magnitude only

ray direction of the path in which light travels scaler instrument which counts current pulses (often used
with a GM tube)
reaction force exerted by a support on a body
second SI unit of time (s)
real image an image which can be formed on a screen
secondary coming later; of less importance
* rectifier changes a.c. to d.c.
* semiconductor diode electronic device which allows
redshift shift in the wavelengths of light from distant current to flow in one direction but not the other
galaxies towards longer wavelengths (the red end of the
spectrum) sensitivity response of a device to a change in input;
precision
reed switch electromagnetic switch
series circuit components connected one after the
refraction bending of rays when they pass from one other; the current is the same at each point in a series
medium to another circuit

* refractive index n; the ratio of the speeds of a wave in significant figures number of figures to which a value is
two different regions given; they indicate the precision of a measurement

regular reflection a parallel beam of light is reflected from sliding friction frictional force acting on a body moving at
a smooth surface such as a mirror, in a parallel beam a constant speed

relative charges of protons, neutrons and electrons +1, 0, * slip rings rings attached to the ends of the coil of an a.c.
–1, respectively generator which rotate with the coil and to which electrical
contact is made
relative motion motion of one object with respect to another
soft in magnetic terms, material such as iron which is easily
relay electromagnetic switch magnetised and demagnetised

renewable can be replaced; cannot be used up solar cells convert sunlight into electricity

resistance opposition of a conductor to the flow of electric solar energy energy from the Sun
current; symbol R, measured in ohms (Ω)
solar panels convert sunlight into thermal energy
resistance of a metallic wire directly proportional to its
length and inversely proportional to its cross-sectional area solenoid long cylindrical coil of wire

resistor conductor designed to have resistance * sonar an echo technique which enables the depth of an
object to be found using ultrasonic waves
resultant force the rate of change in momentum per unit time
spectrum band of colours produced when white light is
* retardation a negative acceleration; velocity decreases separated into its component parts
as time increases

reverberation combination of a sound wave and its echo
which acts to prolong the sound

347

Glossary

* specific heat capacity the energy required per unit mass thermostat a device which keeps the temperature of a room
per unit temperature increase or appliance constant

speed distance travelled per unit time * thoron radioactive gas which emits α-particles

speed–time graph graph of speed on the vertical axis tidal energy flow of tidal water from a high to a low level
plotted against time on the horizontal axis used to generate electricity

* split-ring commutator split ring of copper which rotates time duration; SI unit is the second (s)
with the coil of an electric motor; it enables the current
through the coil to be reversed every half-turn total internal reflection occurs when a light ray does
not cross the boundary between two media; it is totally
* spring constant force per unit extension
reflected at the boundary
stable equilibrium occurs when a body returns to its
original position when slightly displaced and then released * tracer radioisotope injected into a system; the motion or
concentration of the isotope can be monitored, for example
standard notation writing numbers using powers of ten
with a GM tube
starting friction maximum value of a frictional force which
occurs just as a body starts to move transformer two coils (primary and secondary) wound on a
soft iron core which allow an alternating p.d. to be changed
static friction maximum value of a frictional force which
occurs just as a body starts to move from one value to another

* stator (or diaphragm) set of fixed blades (or fixed coils transverse wave direction of vibration is perpendicular to
in an alternator) the direction of travel of the wave

steam turbine steam is used to turn the blades of a rotor tritium 3 HH; isotope of hydrogen with one proton and two
1
strain energy energy stored in a compressed spring or neutrons in the nucleus
elastic material
ultrasound sound wave with a frequency greater than 20 kHz
stretching force force causing a body to change shape
ultraviolet radiation electromagnetic waves having shorter
systematic error error introduced by the measuring device wavelengths than light
(the system)
uniform having the same value
tangent a line touching, but not intersecting, a curve
uniform acceleration constant acceleration
temperature determines the direction in which thermal
energy flows; kinetic theory regards temperature as a measure uniform velocity constant velocity
of the average kinetic energy of the molecules of the body
unstable equilibrium occurs when a body moves further
temporary magnets made of soft iron, lose their away from its original position when slightly displaced and
magnetism easily
then released
* terminal velocity constant velocity reached when the air
resistance upwards equals the downward weight of a falling vacuum a space from which all air has been removed
body
vaporisation change of a liquid to a vapour
thermal energy energy of the molecules in a body
variable quantity that can be changed
thermal power station thermal energy is used to turn
water into steam to drive a turbine and generate electricity variable resistor resistor whose resistance can be changed

thermistor semiconductor device in which the electrical * variation of magnetic field strength the magnetic field
resistance decreases when the temperature increases decreases with distance from a current-carrying wire and

thermometer device for measuring temperature varies around a solenoid

* thermonuclear fusion the combination of light nuclei * vector a quantity which has both magnitude and direction
into a heavier nucleus in a reaction which takes place at a
very high temperature (for example in the Sun) velocity speed in a given direction; change in displacement
per unit time

virtual image an image which cannot be formed on a screen

volt V; unit of p.d.

voltage p.d.; measured in volts (V)

348

Glossary

voltmeter instrument used to measure p.d. the crests of waves in a ripple tank are wavefronts. A line
drawn perpendicular to a wavefront is a ray
volume of a cylinder πr2 × h, where r is the radius and h is
the height of the cylinder wavelength distance between successive crests of a wave

watt SI unit of power; 1 W = 1 J/s weight a gravitational force on an object that has mass

wave energy rise and fall of sea waves used to generate wind turbines convert wind energy into electrical energy
electricity
work measure of amount of energy transferred.
wave equation v = fλ Work done = force × distance moved in the direction of the
force. SI unit is the joule (J)
waveform shape of a wave
X-rays electromagnetic waves with a shorter wavelength
wavefront in two dimensions, it is a line on which the than ultraviolet radiation
particles transmitting the wave are vibrating in phase;

349

Acknowledgements

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350

Index

A atoms 86 stability 50
audibility, limits of 168 toppling 49
absolute zero 89, 94 average orbital speed 278 centripetal force 41–2
acceleration 13 average speed 12 Ceres 280
chain reaction 257
effect of force and mass 38–9 B changes of state 108
equations of motion 17 boiling and evaporation 112
speed–time graphs 14–15 background radiation 260 latent heat 110–11
acceleration of free fall (g) 19 count-rate corrections 261 solidifying and melting 109–10
measurement 20 charge see electric charge
accretion model of the Solar balances 25, 26 charged particles, force acting on in a
System 280 balancing a beam 44 magnetic field 238–9
a.c. generator 231–3 balancing forces 35 Charles’ law 95
action-at-a-distance forces 26, 187 balancing tricks and toys 50 Charon 283
action at points 188 barometers 83 chemical energy 61
air basic quantities 2 circle, area of 4
convection in 118 batteries 193, 211–12 circuit breakers (trip switches) 226
density of 31 beam balance 25 circuits see electric circuits
air bags 66 beams of light 136–7 circuit symbols 209
air resistance 18, 22, 37, 40 Becquerel, Henri 260 circular coil, field due to 234
alcohol, use in thermometers 103 beta (b)-decay 266 circular motion 41–2
Alpha Centauri 287 beta-particles 263 cloud chambers 264
alpha (a)-decay 266 coal 69
alpha-particles 262, 263 dangers of 272 coal fires 124
dangers of 272 particle tracks 264 coastal breezes 118
uses of 270 uses of 270 cobalt 263
alpha-particle scattering Big Bang theory 291–2 coil, turning effect on 239–40
experiment 252–3 bimetallic strips 101–2 collisions 55–6
alternating current (a.c.) 192 biofuels 71 car safety 66
a.c. generator 231–3 biogas 71 conservation of momentum 56
frequency of 193 black dwarf stars 289 elastic and inelastic 66
alternators 232 black holes 290 collision time 58
aluminium, specific heat capacity 107 Bohr, Niels 253 comets 280
americium 260, 270 boiling 87, 112 communications satellites 42, 163
ammeters 190, 191 Bourdon gauge 82 communication systems 164
ampere (A) 190 Boyle’s law 93 commutator 240
amplitude (a) 129 Brahe, Tycho vi compressions 129, 168
analogue signals 164–5 brakes 81 condensation 87
Andromeda galaxy 288 braking distance 66 latent heat of vaporisation 111
angle of incidence 131, 138, 144 Brownian motion 89, 90 conduction of heat 115–16
angle of projection 21 brushes 240 conductors of electricity 186–7, 189
angle of reflection 131, 138 bubble chambers 264–5 ohmic and non-ohmic 201
angle of refraction 144 buildings, energy loss from 123 resistance 198
anode 218 conductors of heat 115–16
antineutrinos 266 C uses of 122
archaeology, radiocarbon conservation of energy 62–3, 65, 230
techniques 271 cancer, diagnosis and treatment 270 conservation of momentum 56
area 4 carbon-14 271 constantan wire 199
area under a graph 16 carbon dioxide constant of proportionality 296
armature 240 constant speed
asteroids 279, 280 emission by fossil fuels 69 distance–time graphs 15
atmospheric pressure 91 greenhouse effect 120–1 speed–time graphs 14
mercury barometer 83 car brakes 81 continuous spectrum 254
atomic bombs 257 car radiators 124 convection 117–18
atomic structure 185 car safety 58, 66 uses of 123
nuclear model 253 car speedometers 247 convection currents 117, 118
nucleus 254–6 cathode 218 convector heaters 224
‘plum-pudding’ model 252 cathode ray oscilloscope (CRO) 171 conventional current 190
Rutherford–Bohr model 253 cells, electric 211–12
Schrödinger model 254 Celsius temperature scale 94, 104
centre of gravity (centre of mass) 47–8
balancing tricks and toys 50
of an irregularly shaped object 48

351

Index displacement–distance graphs 129 direct and alternating 192–3
distance–time graphs 15–16 effects of 190
converging beams 137 at a junction 210
converging lenses 150–2 falling bodies 20 magnetic effect 233–5
cooling, rate of 121 distance travelled measurement of 190, 191–2
cooling by evaporation 112 in series and parallel circuits 210
cooling curves 109 equations of motion 17 electric fields 187
Copernicus, Nicolaus vi speed–time graphs 16 electric heating 224
cosmic microwave background diverging beams 137 electricity
diverging lenses 150–1 paying for 204–5
radiation (CMBR) 292 Doppler effect 291 transmission of 246–7
cosmic rays 260 double insulation 227 electricity generation
coulomb (C) 190 drag 40 energy sources 69–71
Crab Nebula 290 dwarf planets 279, 280 see also power stations
critical angle 146–7 dynamo rule (Fleming’s right-hand electricity meters 204–5
critical value 257 rule) 231 electric lighting 223
crumple zones 58, 66 electric motors 239–40
cubic centimetre (cm3) 4, 5 E power output 203
cubic metre (m3) 4 practical work 241
Curie, Marie 260 E = mc2 257 electric power 202–3
current see electric current Earth 279 of appliances 204
cylinder, volume of 5 measurement of 203
facts and figures 282 electric shock 222–3
D magnetic field 182 electromagnetic induction 229
motion of 276–7 direction of induced e.m.f. 230–1
dams 80 earth (E) wire 224 experiments 229–30
day and night 276 earthing 227 factors affecting induced e.m.f.
d.c. motor 239–40 earthquakes, seismic waves 128, 129,
173 size 230
practical work 241 echoes 168–9 generators 231–3
decay curves 268 estimating the speed of sound 169 mutual induction 243
deceleration (retardation) 13 eddy currents 245 electromagnetic radiation 128
applications 247 dangers of 164
speed–time graphs 14 efficiency 74, 203 electromagnetic spectrum 160–1
declination 182 of power stations 72 gamma rays 164
delocalised electrons 116 of transformers 245 infrared radiation 162
demagnetisation 180 effort 45 light waves 161
density (r) 29 Einstein, Albert 257 microwaves 163
elastic collisions 66 radio waves 162–3
calculations 29–30 elastic strain energy 61 ultraviolet radiation 162
floating and sinking 31 electrical conductors and insulators X-rays 163
measurement 30–1 186–7, 189 electromagnetic waves 161
water and ice 103 electrical safety 222–3 use in communications 164
density, optical 144 fuses 225–6 electromagnets 181
dependent variables 298 trip switches (circuit breakers) 226 uses of 182
depth electric bell 237 electromotive force (e.m.f.) 193,
real and apparent 145 electric cells 211–12 211–12
relationship to pressure 82 electric charge 184 electromagnetic induction 229–31
deuterium 256 dangers of static electricity 188 electron orbits 253
deviation of a light ray 155–6 explanation of 185 electrons 185
dichloromethane 112 gold-leaf electroscope 186 and conduction of electricity 186–7
diffraction 132 positive and negative 184–5 electrostatic energy 61
of radio waves 162–3 uses of static electricity 188 elements, origin of 281
and wave theory 134 electric circuits elliptical orbits 280
diffuse reflection 140 circuit symbols 209 endoscopes 148
diffusion cloud chambers 264 connecting an ammeter 191 energy
digital signals 164–5 connecting a voltmeter 195, 196 conservation of 62–3, 65, 230
diode lasers 218 house circuits 224–7 kinetic 63–4
diodes 201, 218–19 model of 194 potential 64
direct current (d.c.) 192–3 series and parallel 209–13 energy consumption 73
d.c. motor 239–41 electric current (I) 189
direction of an electric field 187 conventional 190
direct proportion 296 definition 190
dispersion of light 155–6, 161
displacement 13
displacement can 30

352

Index

energy density 69 Fleming’s right-hand rule (dynamo gas laws 93, 95–6
energy levels of an atom 254 rule) 231 gas pressure 89, 91
energy sources 68–9
floating and sinking 31 effect of temperature
economic, environmental and fluorescent lamps 223 changes 92, 94
social issues 73 focal length 151
focal point (principal focus) 151 effect of volume changes
non-renewable 69 force multipliers 80 92–3, 96
power stations 72 forces
renewable 69–71 manometers 83
world use of 73 action-at-a-distance 26 gas turbines 72
energy stores 61 centripetal 41–2 gas volume, effect of temperature
energy transfers 60, 61–2 on charged particles in a magnetic
collisions 66 changes 94, 95
efficiency 74 field 238–9 Geiger, Hans 252–3
falling bodies 64–5 on a current-carrying Geiger–Müller (GM) tube 261
measurement of 62 generators 61, 231–3
pendulums 65 conductor 237–8 geostationary satellites 42
and potential difference 194–5 effects of 33, 38–9 geothermal energy 71
practical work 64 extension in springs 34–5 gliding 118
pumped storage 72 gas pressure 89 global warming 69
representation of 63 magnetic 178 gold-leaf electroscope 186
see also thermal energy transfers moments 43–6 gradient (slope) 297
equations, changing the subject of and momentum 57
295–6 Newton’s first law of motion 37 distance–time graphs 15–16
equilibrium 44, 46 Newton’s second law of motion 38–9 speed–time graphs 15
stability 50 Newton’s third law of motion 40–1 graphs 297–8
equinoxes 276, 277 paired 40–1 cooling curves 109
errors resultants 9, 35–6 distance–time 15–16, 20
parallax 3 vector nature of 9 I–V 201
systematic 7 forward-biased diodes 218–19 load–extension 34
zero error 8 fossil fuels 69 speed–time 14–15, 16
ether 112 power stations 72 of wave motions 129
evaporation 87, 112 freezing (solidification) 108, 109 gravitational fields 26
evidence vi latent heat of fusion 110, 111 gravitational field strength 26–7
expansion joints 102 frequency (f ) 6, 129 of a planet 281
explosions 57 of alternating current 193 gravitational potential
extended light sources 138 and pitch 170 energy 61, 64
friction 37, 40 gravity 25–6
F see also air resistance acceleration of free fall 19–20
fulcrum 45 centre of 47–50
falling bodies 18 fundamental frequency 171 of the Moon 277
acceleration of free fall 19–20 fuses 225–6 and planetary motion 284
air resistance 22 fusion, latent heat of 110 Great Red Spot, Jupiter 283
distance–time graphs 20 fusion, nuclear 71, 258 greenhouse effect 69, 120–1
energy transfers 64–5 in stars 286
investigation 19 H
projectiles 21 G
half-life 267–8
Faraday, Michael 229, 230 galaxies 287–8 experimental determination 269
ferromagnetic materials 176, 177, 180 Galileo Galilei vi, 18
fields galvanometers 195, 242 Halley’s comet 280
gamma rays 164, 263, 266 head restraints 66
electric 187 heat conduction 115–16
gravitational 26–7 dangers of 164, 272 heat exchangers 257, 258
magnetic 178–80, 182 uses of 270 heating, electric 224
magnetic effect of a current 234 gap size, effect on diffraction 132 helium, superfluid 94
filament lamps 201 gases hertz (Hz) 129, 193
fire alarms 101 conduction of heat 116 high-temperature alarm 217
fire risk, electrical devices 223 density 29, 31 high-voltage transmission of
fission 257 properties of 87
fixed points, temperature scales 104 structure 88, 89 electricity 246
Fleming’s left-hand rule thermal expansion 100–1 Hooke, Robert 34
(motor rule) 238 gas giants see Jupiter; Neptune; house circuits 224–7
Saturn; Uranus Hubble, Edwin 292
HHuubygbelen’csocnosntasntrtu(cHti0o) n29123–33

353

Index

hydraulic machines 80 measuring g 20 lenses
car brakes 81 measuring resistance 199–200 converging and diverging 150–1
hydraulic jack 80–1 measuring voltage 196–7 magnification 153
measuring your own power 75 magnifying glasses 154
hydroelectric power 70, 72, 73 moments 44, 46 power 153
energy transfers 63 mutual induction 244 practical work 151–2
parallelogram law 36 principal focus 151
hydrogen pinhole camera 137 ray diagrams 153
isotopes 256 rate of cooling 121 spectacles 154–5
thermonuclear reactions 258 reflection of light 139, 140
refraction 144, 147 lever balance 25
I ripple tank 130 levers 45–6
specific heat capacities 106 light
ice specific latent heat of fusion
density of 103 dispersion 155–6
specific latent heat of fusion 110 for ice 110 lenses 150–4
speed of sound 169–70 pinhole camera 137
images stretching a spring 34 ray diagrams 153
formed by a converging lens 152 suggestions for vi rays and beams 136–7
formed by refraction 145 ionisation energy 253 reflection 138–41
position of 140 ionising effect of radiation 260–1 refraction 143–9
properties of 141 ionosphere 163 shadows 138
real and virtual 141 ions 253, 261 speed of 138
iron, magnetisation of 177 light-dependent resistors (LDRs)
impulse 57 iron filings, plotting magnetic 201, 216–17
and collision time 58 fields 180 light-emitting diodes (LEDs) 218
isotopes 256 use in the home 223
independent variables 298 I–V graphs 201 lighting, electric 223
induced magnetism 177 lightning 184
induction motors 240 J lightning conductors 188
inelastic collisions 66 light pipes 148–9
inertia 37 jet engines 57 light sources 136
infrared (IR) radiation 119–20, 162 joulemeter 204 point and extended 138
joules (J) 62, 67 light waves 161
dangers of 164 Jupiter 279 light-years 287, 288
infrared thermometers 124 limit of proportionality 34
ink-jet printers 188 facts and figures 282, 283 limits of audibility 168
insulators, electric 186–7 linear (ohmic) conductors 201
K linear expansivity 102
double insulation 227 linear scales 104
insulators, thermal 116 kaleidoscope 141–2 line spectrum 254
Kelvin temperature scale 94 liquid-in-glass ther
uses of 122–3 kilometre (km) 3 mometers 103
interference (superposition) 134 kilowatt (kW) 75 liquid levels 79
internal energy (thermal energy) kilowatt-hour (KWh) 204 liquid pressure 79–80
kinetic energy 61, 63–4 expression for 82
61, 63, 105 hydraulic machines 80–1
and temperature 105 and pressure 89 water supply systems 80
see also thermal energy transfers and temperature 89, 105 liquids
intruder alarms 216–17 kinetic particle model see particle conduction of heat 116
inverse proportion 297 model convection 117–18
investigations density 29, 31
Brownian motion 90 L properties of 86–7
centre of gravity 48 structure 88
Charles’ law 95 lagging 122 thermal expansion 100
collisions 55–6 lasers 136, 218 litre (l) 5
converging lenses 151–2 latent heat of fusion 110, 111 live (L) wire 224
d.c. motor 241 latent heat of vaporisation 111 load 45
electromagnetic induction 229–30 lateral inversion 141 load–extension graphs 34
electromagnets 181 law of magnetic poles 176–7 longitudinal waves 129, 168
energy transfers 64 law of moments (law of the lever) 45 long sight 154–5
falling bodies 19 law of reflection 138
force and mass, effect on left-hand rule, Fleming’s 238
length measurement 3
acceleration 38
gold-leaf electroscope 186
half-life of thoron 269
magnetic fields 179–80
measuring electric current 191–2
measuring electric power 203

354

Index

loudness 170 medical ultrasound imaging 172 Newton’s first law 37
loudspeakers 168, 236 megawatt (MW) 75 Newton’s second law 38–9
luminous sources 136 melting 86, 108, 109 Newton’s third law 40–1
projectiles 21
M latent heat of fusion 110, 111 speed 12
meniscus 5 speed–time graphs 14–15, 16
magnetic effect of a current 233–5 Mercury 279 velocity 13
applications 235–7 motor effect 237–8
variation around a wire 235 facts and figures 282 electric motors 239–41
mercury barometers 83 motor rule (Fleming’s left-hand rule)
magnetic fields 178 mercury thermometers 103 238
Earth’s 182 mercury vapour lamps 162, 223 moving-coil galvanometer 242
plotting field lines 179–80 metal detectors 247 multimeters 191, 195
metals multiplying factors 80
magnetic force 178 musical notes 170–1
magnetic materials 176, 178 conduction of electricity 189 mutual induction 243
conduction of heat 115–16 practical work 244
soft and hard 177 meteors (shooting stars) 280
magnetic poles 176–7 methane N
magnetic shielding 182 greenhouse effect 120–1
magnetisation 177, 180 use as a fuel 71 National Grid 246
magnetism metre (m) 3 natural gas 69
micrometers 7–8 negative charges 185
induced 177 microwave background radiation 292 Neptune 279
see also electromagnetic induction microwaves 163
magnets dangers of 164 facts and figures 282, 283
electromagnets 181 use in communications 164 neutral (N) wire 224
temporary and permanent 177 Milky Way 287–8, 291 neutral equilibrium 50
uses of 182 millilitre (ml) 5 neutral points, magnetic fields 179
magnification 153 mirages 147 neutrinos 266
magnifying glasses 154 mirrors 138–40 neutrons 185, 255
manometers 83 image properties 141 neutron stars 290
Mars 279 multiple images 147–8 newton (N) 26
exploration of 283 moderator, nuclear reactors 257 Newton, Isaac vi
facts and figures 282 molecules 86 Newton’s cradle 66
Marsden, Ernest 252–3 moments 43 Newton’s laws of motion
mass 25 balancing a beam 44
effect on acceleration 38–9 conditions for equilibrium 46 first law 37
and inertia 37 law of 45 second law 38–9
relationship to weight 27 levers 45–6 third law 40–1
mass defect 257 momentum 55 night sky 287
matter collisions 55–6 noise 170
particle model 87–90 conservation of 56 non-luminous objects 136
states of 86–7 explosions 57 non-magnetic materials 178
measurements and forces 57 non-ohmic conductors 201, 219
area 4 impulse and collision time 58 non-renewable energy sources 69
basic quantities 2 rockets and jets 57 economic, environmental and
electric current 190, 191–2 monitoring satellites 42
electric power 203 monochromatic light 156, 161 social issues 73
length 3 Moon 278 power stations 72
mass 25 average orbital speed 278 normal 138
potential difference 195–6 facts and figures 282 north (N) pole, magnets 176–7
resistance 199–200 gravity 27, 277 nuclear emissions 262–4
scalars and vectors 9 motion of 277 nuclear energy 61, 257
significant figures 3 phases of 277–8 nuclear fuels 69, 72
speed of sound 169–70 rising and setting of 278 economic, environmental and
systematic errors 7 motion
time 6 acceleration 13 social issues 73
units 2 circular 41–2 nuclear fusion 71, 258
vernier scales and micrometers 7–8 distance–time graphs 15–16
volume 4–5 equations of 17 in stars 286
weight 26 falling bodies 18–22 nuclear model of the atom 253
measuring cylinders 5 nuclear reactors 257–8
mechanical waves 128 nuclear stability 267
nucleon number (A) 255

355

Index planets 279–80 pulsars 290
facts and figures 282–3 pumped storage, hydroelectric
nucleons 255 gravitational field strength 281
nucleus of an atom 254–5 power 72
nuclides 256 plotting compass 179 Pythagoras’ theorem 298
plumb lines 48
O ‘plum-pudding’ model of the atom 252 Q
Pluto 279, 283
octaves 170 point sources 138 quality of musical notes 171
Oersted, Hans 233 polarisation 134
ohm (W) 198 polar orbits 42 R
ohmic (linear) conductors 201 poles, magnetic 176–7
Ohm’s law 201 Pole Star 287 radar 163
oil 69 pollution 69 radiant electric fires 224
opaque objects 138 positive charges 185 radiation 119
optical centre of a lens 150 positrons 266
optical density 144 potential difference (p.d., voltage) good and bad absorbers 120
optical fibres 148–9, 164 good and bad emitters 120
orbital speed 278 193–4 greenhouse effect 120–1
orbits 280 and energy transfers 194–5 infrared thermometers 124
measurement of 195–6 rate of cooling 121
and gravity 284 in series and parallel circuits 210 radioactive decay 265, 265–6
satellites 42 potential dividers 199, 201, 215–16 decay curves 268
oscillation, time measurement 6 potential energy 62, 64 half-life 267–9
overtones 171 see also gravitational potential random nature of 269
radioactive waste 69, 272
P energy radioactivity 260
potentiometers (variable resistors) dangers of 272
paired forces 40–1 Geiger–Müller tube 261
parallax error 3 198–9 ionising effect 260–1
parallel beams 137 power 75 nuclear stability 267
parallel circuits particle tracks 264–5
electric 202–4 penetrating power of 262
cells and batteries 211 power of a lens 153 safety precautions 271–2
current 210 powers of 10 2–3 types of nuclear emission 262–4
definition 210 power stations 72 uses of 270–1
house circuits 225 radiocarbon techniques 271
potential difference 211 economic, environmental and radio frequency identification (RFID)
properties of 213 social issues 73 systems 163
resistors 212–14 radioisotopes (radionuclides) 256
parallelogram law 36 generators 232–3 radio telescopes 163
particle model of matter 87–90, 105 pressure 78–9 radiotherapy 270
and conduction of heat 116 radio waves 162–3
and latent heat 111 of gases 89, 91–3 use in communications 164
thermal expansion 100–1 in a liquid 79–82 radium 260, 262
particle tracks 264–5 manometers 83 radon gas 260
pascal (Pa) 78 pressure gauges 82 railway lines 102
pendulums 6–7 pressure law 95–6 range of a projectile 21
energy transfers 65 principal axis of a lens 150 rarefactions 129, 168
penumbra 138 principal focus (focal point) 151 ray diagrams 153
period of a pendulum 6 principle of conservation of energy rays
periscopes 139 62–3, 65, 230 light 136–7
permanent magnets 177 principle of conservation of water waves 131
uses of 182 momentum 56 reactions 46
phase 129 prisms real images 141
phases of the Moon 277–8 dispersion of light 156 reciprocals 295
photons 253 refraction of light 155–6 rectangle, area of 4
pinhole camera 137 totally reflecting 148 rectangular block, volume of 5
pitch 170 problem solving 295 rectification 219
plane mirrors 140 progressive waves 128 red giant stars 289
image properties 141 longitudinal 129 redshift 291
plane polarisation 134 transverse 128 red supergiant stars 289
planetary motion 280, 284 projectiles 21 reed switches 236
theories of vi proportion (variation) 296–7
planetary nebulae 289 proton number (Z) 255
protons 185, 255
356 protostars 288

Index

reflection of light 138–9 ring main circuit 225 field due to 234
image properties 141 ripple tanks 130–2 solidification (freezing) 108, 109
position of the image 140 rockets 57
real and virtual images 141 rotors 72 latent heat of fusion 110, 111
regular and diffuse 140 rulers 3 solids
total internal reflection 146–9
systematic errors 7 density 29
reflection of radio waves 163 Rutherford, Ernest 252–3 properties of 86
reflection of sound 168–9 Rutherford–Bohr model of the atom 253 structure 88
reflection of water waves 131 thermal expansion 100
S sonar 172
and wave theory 133 sound waves 61–2, 129, 167–8
refraction of light 143–4 safety, electrical 222–3 limits of audibility 168
Sankey diagrams 63 longitudinal nature of 168
critical angle 146 satellites 42, 163 musical notes 170–1
by a prism 155–6 Saturn 279 reflections and echoes 168–9
real and apparent depth 145 speed of 169–70
refraction of water waves 131 facts and figures 282, 283 ultrasound 171–2
and wave theory 134 scalars 9 south (S) pole, magnets 176–7
refractive index 145–6 space missions 283
and critical angle 147 speed 13 specific heat capacity 104–6
regular reflection 140 Schrödinger model of the atom 254 of aluminium 107
relays 217, 235–6 scientific enquiry v–vi determination of 106–7
renewable energy sources 69–71 sea breezes 118 of water 106–7
economic, environmental and seasons 277 specific latent heat of fusion 110
seat belts 58, 66 specific latent heat of vaporisation 111
social issues 73 second (s) 6 spectacles 154–5
power stations 72 seismic waves 128, 129, 173 spectrum
residual current circuit breaker self-righting toys 50 of an atom 254
(RCCB) 226 semiconductor diodes 201, 218–19 electromagnetic 160–5
resistance 197–8 semiconductors 216 visible 156
effect of temperature 215 series circuits speed 12
measurement of 199–200 distance–time graphs 15–16
of a metallic wire 200 cells and batteries 211 equations of motion 17
Ohm’s law 201 current 210 of a wave 129
of skin 222 potential difference 210–11 speed of light 138, 161
resistivity 200 resistors 212 and refraction 145
resistors 198 shadows 138 speed of sound 169–70
colour code 214 shooting stars (meteors) 280 speed–time graphs 14–15
light-dependent 201, 216–17 short sight 154 area under 16
in series and parallel circuits 212–14 SI (Système International d’-Unités) sport, impulse and collision time 58
thermistors 201, 215, 217 system 2 spring balances 26
variable 199 significant figures 3 spring constant (k) 35
resultant force 37, 57 sliding (dynamic) friction 40 springs, extension in 34–5
resultant of two forces 9, 35–6 smoke alarms 270 square, area of 4
reverberation 169 solar cells 69–70 square metre (m2) 4
reverse-biased diodes 218–19 solar energy 69, 73 stability 50
rheostats 199 Solar System 279–80 stable equilibrium 50
right-hand grip rule 234–5 origin of 280–1 stable phase of a star 288–9
right-hand rule, Fleming’s 231 planets 282
right-hand screw rule 234 travel times 281
solenoids 180

357

Index and kinetic energy 89, 105 energy losses 245
and rate of emission of step-up and step-down 244
standard notation 2–3 transmission of electricity 246
stars radiation 120 power loss 247
and thermal energy 105 Trans-Neptunian Objects (TNOs) 279
colour of 286, 288 temperature scales 94, 104 triangle, area of 4
life cycle 288–90 temporary magnets 177 trip switches (circuit breakers) 226
night sky 287 electromagnets 181 tritium 256
nuclear reactions 286 terminal velocity 22 tsunami waves 129
origin of 288 theories vi tuning forks 170
see also Sun thermal energy (internal energy) turbines 72
starting (static) friction 40 61, 63, 105 turning effect of a force see moments
states of matter 86–7 and temperature 105
static electricity 184 thermal energy transfers 115 U
dangers of 188 applications 122–4
uses of 188 conduction 115–16 UHF (ultra-high frequency) radio
see also electric charge convection 117–18 waves 163
stators 72 energy loss from buildings 123
steam turbines 72 radiation 119–20 ultrasound 171
steel, magnetisation of 177 thermal expansion 100–1 uses of 172
step-up and step-down bimetallic strips 101–2
transformers 244 linear expansivity 102 ultraviolet (UV) radiation 162
sterilisation, use of g-radiation 270 liquid-in-glass dangers of 164
storage heaters 224
straight-line graphs 297 thermometers 103 umbra 138
straight wire, field due to 234 precautions against 102 uniform (constant) velocity 13
stroboscope 130 uses 101 units of electricity 204–5
strontium 263 water 103 Universe 290–1
sulfur dioxide 69 thermal power stations 72, 232–3
Sun 286, 287 thermals 118 age of 292–3
as an energy source 71 thermistors 201, 215, 217 Big Bang theory 291–2
facts and figures 282 thermometers expansion of 291–2
rising and setting of 276–7 infrared 124 unstable equilibrium 50
thermonuclear reactions 258 liquid-in-glass 103 uranium 257, 260
sunlight, protection from 164 thermonuclear reactions 258 Uranus 279
superconductors 94 thermostats 101–2 facts and figures 282, 283
superfluids 94 thickness gauges 270 U-tube manometer 83
supernovae 290 thoron, half-life of 269
as origin of elements 281 three-heat switches 224 V
superposition see interference tickertape timers 6
sweating 112 tidal energy 70, 71, 73 vacuum 91
switches 224, 225 time 6 vacuum flasks 124
systematic errors 7 top-pan balance 25 van de Graaff generator 189
toppling 49 vaporisation, latent heat of 111
T total internal reflection 146–8 variable resistors (potentiometers)
optical fibres 148–9
tangents, gradient of 16 tracers, radioactive 270–1 198–9
temperature transformer equation 244–5 variables 298
transformers 242–3 vector addition 9
effect on gas pressure 92 vectors 9
effect on gas volume 94, 95
effect on resistance 215 acceleration 13
gravitational field strength 26–7
momentum 57
velocity 13

358

velocity 13 specific latent heat of fusion Index
circular motion 41 for ice 110
and kinetic energy 63–4 seismic 173
terminal 22 specific latent heat of sound 167–72
vaporisation 111 transverse 128
ventilation 123 tsunami 173
Venus 279 thermal expansion 103 wave speed (v) 129
water supply systems 80 wave theory 133–4
facts and figures 282 water waves 128 weight 25–6
vernier scales 7–8 relationship to mass 27
VHF (very high frequency) ripple tank experiments 130–2 wet suits 123
watt (W) 75, 202 white dwarf stars 289
radio waves 163 wave energy 70 wind turbines 70, 73
virtual images 141 wave equation 129–30, 161 wires, resistance of 200
visible spectrum 156 waveforms of musical notes 171 wood fires 124
voltage see potential difference wavefronts 131 work done 62, 67–8
voltmeters 195–6 wavelength (l) 129
volts (V) 193, 194, 202 X
volume 4–5 effect on diffraction 132
waves 128 X-rays 163
effect on gas pressure 92–3, 96 dangers of 164
of an irregularly shaped solid 30 description of 129
diffraction 132, 134 Z
W electromagnetic 161
longitudinal 129 zero error 8
water reflection 131, 133
conduction of heat 116 refraction 131, 134
specific heat capacity 106–7 ripple tank experiments 130–2

359