GCSE Physics

Some of the content is designated for the higher tier candidates only. This content is printed in
bold.

P1: Electricity and Magnetism
• Units
• Mains electricity
• Energy and potential difference in circuits
• Electric charge
• Electromagnetism
• Electromagnetic induction

Units
Candidates will be assessed on their ability to:
• use the following units: ampere (A), coulomb (C), ohm (O), volt (V), watt (W), kilowatthour (kWh) (P1.01)

Mains electricity
Candidates will be assessed on their ability to:
• identify the live, neutral and earth conductor in a correctly-wired plug and recall the colour of the insulation used on each conductor (P1.02)
• recall the hazards of electricity including frayed cables, long cables, damaged plugs, water around sockets and pushing metal objects into sockets (P1.03)
• describe the uses of insulation, double insulation, earthing, fuses and circuit breakers in a range of domestic appliances (P1.04)
• recall that electrical heating is used in a variety of ways in domestic contexts (P1.05)
• understand that a current in a resistor results in the electrical transfer of energy and an increase in temperature (P1.06)
• recall and use the quantitative relationship between power, current and voltage:
power = current × voltage P = I × V
and apply the above relationship to the selection of appropriate fuses (P1.07)
• calculate the energy used by domestic appliances in kilowatt-hours and calculate domestic electricity bills, based on meter readings (P1.08)
• use the quantitative relationship between energy transferred, current, voltage and time:
energy transferred = current × voltage × time E = I × V × t (P1.09)
• recall that mains electricity is alternating current (a.c.) and understand the difference between this and the direct current (d.c.) supplied by a cell (P1.10)

Energy and potential difference in circuits
Candidates will be assessed on their ability to:
• explain whether a series or parallel circuit is more appropriate for a range of applications, including domestic lighting (P1.11)
• understand that the current in a series circuit depends on the applied voltage and the number and nature of other components (P1.12)
• describe how current varies with voltage in wires, resistors, metal filament lamps and diodes and how this can be investigated experimentally (P1.13)
• describe the qualitative effect of changing resistance on the current in a circuit (P1.14)
• describe the qualitative variation of resistance of LDRs with illumination and of thermistors with temperature (P1.15)
• recall and use the quantitative relationship between voltage, current and resistance:
voltage = current × resistance V = I × R (P1.16)
• understand that current is rate of flow of charge (P1.17)
• recall and use the quantitative relationship between charge, current and time:
charge = current × time Q = I × t (P1.18)
• recall that electric current in solid metallic conductors is a flow of negatively charged electrons (P1.19)
• recall that electric current in molten or dissolved electrolytes is a flow of negatively charged ions to the positive terminal and positively charged ions to the negative terminal
(P1.20)
• recall that:
- voltage is the energy transferred per unit charge passed
- the volt is a joule per coulomb (P1.21)

Electric charge
Candidates will be assessed on their ability to:
• describe common materials which are electrical conductors or insulators including metals and plastics (P1.22)
• recall that insulating materials can be charged by friction (P1.23)
• explain that positive and negative electrostatic charges are produced on materials by the loss and gain of electrons (P1.24)
• recall that there are forces of attraction between unlike charges and repulsion between like charges (P1.25)
• explain common electrostatic phenomena, including shocks from car doors and synthetic fabrics, in terms of the movement of electrons (P1.26)
• describe the potential dangers and uses of electrostatic charges generated in everyday situations, eg fuelling aircraft and tankers, photocopiers and inkjet printers (P1.27)

Electromagnetism
Candidates will be assessed on their ability to:
• recall that a force is exerted on a current-carrying wire in a magnetic field and the application of this effect in simple d.c. electric motors and loudspeakers (P1.28)
• understand that when a wire carrying a current is perpendicular to a magnetic field, the resulting force is perpendicular to both (P1.29)

Electromagnetic induction
Candidates will be assessed on their ability to:
• recall that a voltage is induced in a conductor when it moves through a magnetic field or when a magnetic field changes through a coil and recall the factors which affect the size of the induced voltage (P1.30)
• describe the generation of electricity by the rotation of a magnet within a coil of wire and of a coil of wire within a magnetic field and the factors which affect the size of the induced voltage (P1.31)
• recall the structure of a transformer and understand that a transformer changes the size of an alternating voltage by having different numbers of turns on the input and output sides (P1.32)
• explain the use of step-up and step-down transformers in the large-scale generation and transmission of electrical energy (P1.33)
• recall and use the quantitative relationship between input (primary) and output (secondary) voltages and the turns ratio for a transformer:
( )
( )
( )
turns(secondary)
= turns primary
voltage secondary
voltage primary
S
P
S
P
n
= n
V
V (P1.34)

P2: Forces and Motion

• Units
• Movement and position
• Forces and movement
• Forces and shape
Units
Candidates will be assessed on their ability to:
• use the following units: kilogram (kg), metre (m), metre2 (m2), metre3 (m3), metre/second (m/s), metre/second2 (m/s2), newton (N), pascal (Pa) (P2.01)
Movement and position
Candidates will be assessed on their ability to:
• understand distance – time graphs (P2.02)
• explain the difference between speed and velocity (P2.03)
• recall and use the quantitative relationship between acceleration, velocity and time:
time taken
accelerat ion = change in velocity
( ) a
v u
t
=
-
(P2.04)
• interpret speed-time graphs and determine acceleration from the gradient of the graph (P2.05)
• determine the distance travelled from the area between the curve and the time axis (P2.06)
Forces and movement
Candidates will be assessed on their ability to:
• recall a brief history of our understanding of forces including:
- the Greek view – a single force needed to sustain motion
- Galileo and Newton – balanced forces allow an object to continue in uniform motion in a straight line or to remain at rest
- Newton – gravitational attraction acts between all masses (P2.07)
• recall that when two bodies interact, the forces they exert on each other are equal and opposite (P2.08)
• understand how to add forces which act along a line (P2.09)
• understand that friction can produce both accelerating and retarding forces (P2.10)
• recall and use the quantitative relationship between unbalanced force, mass and acceleration and apply this relationship to vehicular and human movement
force = mass × acceleration F = m × a (P2.11)
• recall and use the quantitative relationship between weight, mass and g:
weight = mass × g W = m × g (P2.12)
• explain the forces acting on falling objects and why falling objects reach a terminal velocity (P2.14)
ideas
• understand that the stopping distance of a vehicle is the sum of the thinking distance and the stopping distance (P2.15)
• describe the factors affecting vehicle stopping distances including speed, mass, road condition and reaction time (P2.16)
Forces and shape
In order to meet statutory requirements, candidates following the Welsh National Curriculum
should be taught the principle of moments and its application to situation involving one pivot.
Candidates will be assessed on their ability to:
• understand that the upward forces on a light beam supported at its ends vary with the position of a heavy object placed on the beam (P2.17)
• describe how extension varies with applied force for a range of materials including springs and/or rubber bands (P2.18)
• recall that particles in a gas have random motion and that they exert a force on the walls of the container (P2.19)
• understand the relationship between the pressure and volume of a fixed mass of gas at constant temperature and use the quantitative relationship:
P1 × V1 = P2 × V2 (P2.20)

P3: Waves

• Units
• Properties of waves
• The Earth’s layered structure
• The electromagnetic spectrum
• Light and sound

Units

• use the following units: hertz (Hz), kilohertz (kHz), megahertz (MHz), metre/second (m/s) (P3.01)

• describe longitudinal and transverse waves in ropes, springs and water (P3.02). The waves which travel along ropes and across the surface of water
are transverse waves: the disturbances in the substance through which the waves travel is at right angles to the direction in which waves themselves travel.
The waves which travel through springs may also be longitudinal: the disturbances in the spring are along the same direction as that in which the waves themselves travel. (Waves travelling along a rope or spring, or across the surface of water, can be reflected. Waves travelling across the surface of water can also be refracted.
The change in the speed of water waves when they cross the boundary between two different depths causes a change in their direction (refraction), unless the direction of travel of the waves is along a normal.)
• state the meaning of amplitude, frequency, wavelength and period of a wave (P3.03). Waves can be produced in ropes and springs and on the surface of
water. When waves travel along ropes or springs or across the surface of water they set up regular patterns of disturbances:
• the maximum disturbance caused by a wave is called its amplitude;
• the distance between a particular point on one disturbance and the same point on the next is called the wavelength;
• the number of waves each second produced by a source (or passing a particular point) is called the frequency, and is measured in hertz (Hz).
• recall that waves transfer energy and information without transferring matter (P3.04)
• recall and use the quantitative relationship between the speed, frequency and wavelength of a wave:

• use the quantitative relationship between frequency and time period:

frequency = 1 / time period f = 1 / T (P3.06)

• use the above relationships in a wide range of contexts including sound waves and electromagnetic waves (P3.07)
• understand that waves can be diffracted through gaps or when they pass an edge and that the extent of diffraction depends on the wavelength and the physical dimension (P3.08). When a wave moves through a gap, or past an obstacle, it spreads out from the edges. This is called diffraction.

• understand that the different ways in which longitudinal and transverse waves are transmitted through the Earth, and their paths and times of
travel, provide evidence for the Earth’s layered structure: crust, mantle, outer (liquid) core, inner core (P3.09) Our knowledge of the structure of the Earth comes mainly from studying how the shockwaves from earthquakes (seismic waves) travel through it. These waves are detected using seismographs. The Earth is nearly spherical and has a layered structure comprising:
• a thin crust;
• a mantle, extending almost halfway to the Earth’s centre which has all the properties of a solid except that it can flow very slowly;
• a core, with just over half of the Earth’s radius, made of nickel and iron the outer part of which is liquid and the inner part of that is solid. The overall density of the Earth is much greater than the mean densities of the rocks which form the crust. This indicates that the interior of the Earth is made of material different from, and denser than, that of the crust.

• recall that the Earth’s outermost layer, the lithosphere, is composed of plates in relative motion and that plate tectonic processes result in the formation, deformation and recycling of rocks (P3.10)
• understand that at plate boundaries, plates may:
- slide past each other, causing earthquakes
- move towards each other, taking rock into the mantle
- move away from each other, resulting in volcanoes and/or formation of new rocks (P3.11)

The edges of land masses (continents) which are separated by thousands of kilometres of ocean (e.g. the east coast of South America and the west coast of Africa):
• have shapes which fit quite closely;
• have similar patterns of rocks and fossils.
This suggests that they were once part of a single land mass which has split and been moved apart. The Earth’s lithosphere (the crust and the upper part of the mantle) is cracked into a number of large pieces (tectonic plates) that are constantly moving at relative speeds of a few centimetres per year as a result of convection currents within the Earth’s mantle driven by heat released by natural radioactive processes. Earthquakes and/or volcanic eruptions occur at the boundaries
between tectonic plates. Candidates should be able, when provided with information about the complex probable causes of earthquakes and volcanic eruptions
and the difficulty of making measurements of many of the factors involved, to explain why scientists cannot yet accurately predict when they will occur. At one time it was believed that the major features of the Earth’s surface were the result of the shrinking of the crust as the Earth cooled down following its formation. Candidates should be able, when provided with appropriate additional information, to explain why Wegener’s theory of crustal movement (continental drift) was not generally accepted until more than 50 years after it was proposed. Tectonic plates:

• may slide past each other. This is happening along the Californian coast giving rise to earthquakes;

• may move towards each other. As this happens, a thinner, denser oceanic plate can be driven down (subducted) beneath a thicker granitic continental plate where it partially melts. The continental crust is compressed, causing folding, faulting and metamorphism. Earthquakes are produced and magma may rise through the continental crust to form volcanoes. This is happening along the western side of South America (the Andes);
• may move away from each other by magma. This causes fractures which are filled by magma producing new, basaltic, oceanic crust. This is known as sea floor spreading and is happening along oceanic ridges, including the mid-Atlantic ridge. The iron-rich minerals in the magma record the direction of the Earth’s
magnetic field at the time when the rising magma solidified. Magnetic reversal patterns in oceanic crust occur in stripes parallel to oceanic ridges, matching the period reversals of the Earth’s magnetic field and so supporting the concept of sea floor spreading.

#All types of electromagnetic waves travel at the same speed through space, often referred to as the 'speed of light'. The various types of electromagnetic radiation form a continuous spectrum extending far beyond each end of the visible spectrum:
highest shortest
frequency wavelength
gamma rays
X-rays
ultraviolet rays
light
infra red rays
microwaves
radio waves
lowest longest
frequency wavelength
Different wavelengths of electromagnetic radiation are reflected, absorbed or transmitted differently by different substances and types of surface. When radiation is absorbed, the energy it carries:
• makes the substance which absorbs it hotter;
• may create an alternating current with the same frequency as the
radiation itself.
The uses and effects of different types of radiation depend on these and other properties. Radio waves are used to transmit radio and TV programmes between
different points on the Earth’s surface. Shorter wavelength radio waves are reflected from an electrically charged layer in the Earth’s upper atmosphere. This enables them to be sent between distant points despite the curvature of the Earth’s surface. Microwave radiation of wavelengths which can pass easily through the Earth’s atmosphere is used to send information to and from satellites and within mobile phone networks. Microwave radiation, with wavelengths strongly absorbed by water molecules, is used for cooking. Infra red radiation is used in grills, toasters and radiant heaters, in optical fibre communication and for the remote control of TV sets
and VCRs. Light is not only used for seeing but can also be sent along optical fibres, for example in endoscopes used by doctors to see inside patients’ bodies.#

#More information can be carried than by sending electrical signals through cables of the same diameter. There is also less weakening of the signal in optical fibres.

Ultraviolet radiation is used in sunbeds. Special coatings which absorb ultraviolet radiation and emit the energy as light, are used in fluorescent lamps and security coding.

X-radiation is used to produce shadow pictures of materials which
X-rays do not easily pass through, including bones and metals.
Gamma radiation is used to:
• kill harmful bacteria in food;
• sterilise surgical instruments;
• kill cancer cells.
Different types of radiation have different effects on living cells:
• microwaves are absorbed by the water in cells, which may be damaged or killed by the heat released;
• infra red radiation is absorbed by skin and is felt as heat;
• ultraviolet radiation can pass through skin to deeper tissues. The darker the skin, the more ultraviolet it absorbs and the less reaches into deeper tissues;
• X-radiation and gamma radiation mostly pass through soft tissues, but some is absorbed by the cells. High doses of ultraviolet radiation, X-radiation and gamma radiation can kill normal cells. Lower doses of these types of ionising radiation can cause normal cells to become cancerous. Candidates should be able, when provided with appropriate information, to evaluate:
• the dangers, or possible dangers, of exposure to different types of electromagnetic radiation and to radiation from radioactive substances;
• measures that can be taken to reduce such exposure.

Information such as speech or music can be converted into electrical signals so that it can be sent long distances through cables or using electromagnetic waves as carriers. Information can also be converted into light or infra red signals and sent along optical fibres. Signals which vary continuously in amplitude and/or frequency, in the same way that the sound waves of speech or music do, are called analogue signals. Signals can also be coded as a series of pulses. The signal then has
only two states, on or off. Signals of this type are called digital signals.#

#The advantages of digital signals are:
• their higher quality – the signals do not change their information during the transmission process;
• their information carrying capacity – more information can be sent in a given time via a given cable, optical fibre or carrier wave than with analogue signals.

As signals travel they become weaker. Random additions to the signal (noise) may also be picked up. With analogue signals, different frequencies within the signal may weaken to different extents. Each time the signal is amplified, these differences, and any noise that has been picked up, are also amplified. This means that the signal becomes less and less like the original signal; its quality deteriorates. With digital signals, even though pulses weaken with distance, they are
still recognisable as “on” states, whereas noise is generally of low amplitude and is ignored (i.e. interpreted as “off”). The quality of a digital signal is maintained, therefore, during the transmission process.#

There are converging and diverging lenses. Candidates should be able to:
• identify the difference between converging and diverging lenses;
• draw how parallel rays of light pass through these lenses;
• identify the position of the focus of both a converging and diverging lens;
• know the difference between a real and a virtual image.
In a camera, a converging lens is used to produce an image of an object on a film. The image is smaller than the object and nearer to the lens.

Candidates should be able to:
• construct ray diagrams to show the formation of real images by converging lenses;
• construct ray diagrams to show the formation of virtual images by converging lenses;
• explain the use of a converging lens as a magnifying glass, and in a camera.#

• understand that light is part of a continuous electromagnetic spectrum which includes radio, microwave, infra-red, visible, ultraviolet, X-ray and gamma ray radiations and that all these waves travel at the same speed in free space (P3.12)
• recall the order of the electromagnetic spectrum in decreasing wavelength and increasing frequency including the colours of the visible spectrum (P3.13)
• recall some uses of electromagnetic radiations including:
- radio waves: broadcasting and communications
- microwaves: cooking and satellite transmissions
- infra-red: heaters, grills, night vision and remote controls
- visible light: optical fibres and photography
- ultraviolet: sunbeds, crime prevention and fluorescent lamps
- X-rays: observing the internal structure of objects and materials, medical applications
- gamma rays: sterilising food and medical equipment (P3.14)
• recall the detrimental effects of excessive exposure of the human body to electromagnetic waves of increasing frequencies including:
- microwaves: internal heating of body tissue
- infra-red: skin burns
- ultraviolet: damage to surface cells and blindness
- gamma rays: cancer, mutation (P3.15)

Electromagnetic radiation and sound are also diffracted which supports the idea that they travel as waves. Because of diffraction:
• sounds can sometimes be heard in the shadow of buildings;
• radio signals can sometimes be received in the shadow of hills.
Waves having a longer wavelength are more strongly diffracted.

Light and sound

• recall that light waves are transverse waves which can be reflected, refracted and diffracted (P3.16). When a ray of light is reflected from a flat, shiny surface (plane mirror) the angle at which it leaves the surface is the same as the angle at which it meets the surface. Rays of light change direction (are refracted) when they cross the boundary between one transparent substance and another, unless they meet the boundary at right angles (along a normal). Sounds are also refracted, i.e. their direction is changed when they cross the boundary between two different substances at an angle other than a right angle. The reflective and refractive behaviour of waves in springs and water suggests that light and sound:
• also travel as waves;
• are refracted because they travel at different speeds in different substances (media). When rays of light pass through prisms their direction may be
changed. When white light is used, a spectrum is produced. The spectrum is produced because white light is made up of many different colours. Different colours of light are refracted by different amounts; red light is refracted least and violet light most. Whereas sound waves travel through solids, liquids and gases as longitudinal waves, light waves are transverse waves and can travel through a vacuum, i.e. they do not need a medium. Sounds bounce back (reflect) from hard surfaces. Echoes are sound reflections.
• describe the role of total internal reflection in transmitting information along optical fibres and in prisms (P3.17). When light travels from glass, Perspex or water into air some of the light is reflected from the boundary. If the angle between the ray and a normal is greater than a certain angle (called the critical angle), all of the light is reflected inside the glass, Perspex or water. This is called total internal reflection. When light travels down an optical fibre, all the light may stay inside
the fibre until it emerges from the other end. This is because light travels down optical fibres by repeated total internal reflection. Candidates should be able to describe, using a suitable diagram, one other use of total internal reflection.

Give examples of effects tht show that light travels in straight lines
Draw ray diagrams to show the result of varying the object distance or the length of the camera.
Draw digrams to show how shadows are formed with both point and extended sources, and use the terms umbra and penumbra
Recall that (a) light travels much faster than sound - 3 x 10⁸ m/s versus ~ 300 m/s and (b) speed depends on nature and properties of the medium.
State the laws of reflection
Describe an experiment to show that, for reflection of ligth, the angle of incidence equals the angle of refraction

• understand the difference between analogue and digital signals (P3.18)
• describe how digital signals can carry more information (P3.19)
• recall that sound waves are longitudinal waves which can be reflected, refracted and diffracted (P3.20) Sounds are produced when objects vibrate. The greater the size (amplitude) of vibrations the louder the sound. The number of complete vibrations each second is called the frequency (hertz, Hz). The higher the frequency of a sound the higher its pitch. Candidates should be able to compare the amplitudes and frequencies of sounds from diagrams of oscilloscope traces. Electronic systems can be used to produce electrical oscillations with any frequency. These electrical oscillations can be used to produce ultrasonic waves which have a frequency higher than the upper limit of the hearing range for humans.
• recall that the frequency range for human hearing is 20 Hz – 20 000 Hz (P3.21) Sound waves travel through solids, liquids and gases as longitudinal waves.
• understand the nature of ultrasound as high-frequency sound and its applications in scanning, cleaning and range or direction finding (P3.22) Ultrasonic waves can be used:
• in industry for cleaning and for quality control;
• in medicine for pre-natal scanning.

Ultrasonic waves are partly reflected when they meet a boundary between two different media. The time taken for the reflections of ultrasonic pulses to reach a detector (usually placed near to the source) is a measure of how far away such a boundary is. This idea is used in industry to detect flaws in metal castings and in medicine for pre-natal scans. Information about the time taken for reflections to travel is usually processed to produce a visual display. Ultrasonic waves in liquids can also be used for cleaning delicate mechanisms without having to disassemble them.

P4: The Earth and Beyond
• The Solar system
• The rest of the Universe

The Solar system

• interpret physical data on the planets, particularly with regard to their masses and their orbits in the Solar system (P4.01)
• describe the differences between the orbits of a planet and a moon, and also of a comet, and describe the different types of orbit of satellites around the Earth
(P4.02)
• understand that the movements and orbits of planets and moons, and of comets and satellites, are determined by gravitational forces (P4.03)
The rest of the Universe

• recall that the Sun is one of many millions of stars in a huge group called the
Milky Way galaxy (P4.04)
• describe the Universe as a system consisting of an enormous number of galaxies
and be aware of the search for evidence of extraterrestrial life (P4.05)
• describe how stars form from very large clouds of hydrogen, helium and dust
which collapse under the influence of gravity so that the core becomes hot
enough for nuclear reactions to begin (P4.06)
• recall that small stars, like the Sun, eventually become red giants and later
become white dwarfs (P4.07)
• describe the ‘Big Bang’ theory of the origin of the Universe and consider other
theories such as the ‘steady state’ theory (P4.08)
• recall evidence for the ‘Big Bang’ theory including the different red shifts of
light from distant galaxies and the background microwave radiation (P4.09)
• explain how the future of the Universe depends on the amount of mass present
(P4.10)

P5: Energy Resources and Energy Transfer
• Units
• Energy transfer
• Work and power
• Energy resources and electricity generation
Units
Candidates will be assessed on their ability to:
• use the following units: degree Celsius (oC), joule (J), newton (N), watt (W),
kilowatt (kW), megawatt (MW) (P5.01)
Energy transfer
Candidates will be assessed on their ability to:
• describe energy transfers involving the following forms of energy: thermal, light,
electrical, sound, movement (kinetic), chemical, nuclear and potential (elastic
and gravitational) (P5.02)
• understand that energy is conserved (P5.03)
• recall that efficiency is the proportion of energy transferred to useful work and
apply this to everyday situations (P5.04)
• describe a variety of everyday and scientific devices and situations explaining the
fate of the input energy in the above terms including their representation by flow
diagrams (Sankey diagrams) (P5.05)
• describe how insulation is used to reduce energy transfers from buildings and the
human body (P5.06)
• understand that many insulating materials make use of the insulating
properties of air that is not free to form convection currents (P5.07)

Candidates will be assessed on their ability to:
• recall and use the quantitative relationship between work, force and distance
moved in the direction of the force:
work done = force × distance moved W = F × d (P5.08)
• understand that work done is equal to energy transferred (P5.09)
• recall and use the quantitative relationships:
gravitational potential energy = mass × g × height GPE = m × g × h
kinetic energy = ½ × mass × speed2 KE = ½ × m × v2 (P5.10)
• understand how conservation of energy produces a quantitative link between
potential energy, kinetic energy and work (P5.11)
• describe power as the rate of transfer of energy or the rate of doing work (P5.12)
• use the quantitative relationship between power, work done (energy transferred)
and time taken:
time taken
work done
power =
t
P = W (P5.13)
Energy resources and electricity generation
Candidates will be assessed on their ability to:
• understand a range of energy transfer chains illustrating the environmental
implications of generating electricity, including:
- the use of wind and water
- geothermal resources
- solar heating systems and electricity production through solar cells
- fossil fuel reserves
- nuclear power (P5.14)
• describe the advantages and disadvantages of methods of large-scale
electricity production using a variety of renewable and non-renewable
resources (P5.15)

P6: Radioactivity
• Units
• Radioactivity
Units
Candidates will be assessed on their ability to:
• use the following unit: becquerel (Bq) (P6.01)
Radioactivity
Candidates will be assessed on their ability to:
• describe the structure of an atom in terms of protons, neutrons and electrons and
use symbols such as 14
6 C to describe particular nuclei (P6.02)
• understand the terms atomic (proton) number and mass (nucleon) number and
explain the existence of isotopes (P6.03)
• understand that alpha and beta particles and gamma rays are ionising radiations
emitted from unstable nuclei in a random process (P6.04)
• describe the nature of alpha and beta particles and gamma rays and recall that
they may be distinguished in terms of penetrating power (P6.05)
• describe the effects on the atomic and mass numbers of a nucleus of the
emission of each of the three main types of radiation and understand how to
complete balanced nuclear equations (P6.06)
• understand that ionising radiation can be detected using a photographic film or a
Geiger-Müller detector (P6.07)
• recall the existence of background radiation from the Earth and from space,
including the regional variations in the United Kingdom, eg because of radon gas
released from rocks (P6.08)
• understand that the activity of a radioactive source decreases over a period of
time and is measured in becquerels (P6.09)
• recall the term half-life and understand that it is different for different radioactive
isotopes (P6.10)
• use the concept of half-life to carry out simple calculations on activity (P6.11)
• describe the uses of radioactivity in medical and non-medical tracers, in
radiotherapy and in the radioactive dating of archaeological specimens and rocks
(P6.12)
• describe the dangers of ionising radiations including:
- radiation can cause mutations in living organisms
- radiation can damage cells and tissue
- the problems arising in the disposal of radioactive waste (P6.13)

P7: Comunications
• Units
• Communications systems
• Transmitting and receiving radio waves
• Satellites
Units
Candidates will be assessed on their ability to:
• use the following units: metre (m), second (s), metre/second (m/s), metre/second2 (m/s2), newton (N), hertz (Hz) (P7.01)
Communication systems
Candidates will be assessed on their ability to:
• recall that communications systems can be broken down into a number of blocks, each having specific functions (P7.02)
• recall the terms used for the various building blocks and their associated functions, including:
- encoder
- modulator
- decoder
- storage
- transmitter
- receiver
- transducer
- amplifier (P7.03)
• recall how light can be encoded to transmit information via an optical fibre (P7.04)
• describe the advantages of using digital signals rather than analogue signals (P7.05)
• recall the different methods of storage and retrieval of information, including:
- digital storage as used with CD players
- analogue storage as used in record players
- use of magnetic tape, photo-diode and diode-laser (P7.06)
• understand the physical principles of a variety of transducers, including:
- moving coil loudspeaker
- moving coil microphone
- erase, record and playback heads of a tape recorder (P7.07)
• understand the terms noise and attenuation and how these can affect the quality of the received signal (P7.08)
• recall the use of regenerators and repeaters in electrical cable and optical fibre communications (P7.09)

Transmitting and receiving radio waves
Candidates will be assessed on their ability to:
• recall a brief history of the development of sending and receiving information including:
- communication by telegraph and telephone
- wireless transmissions leading to radio and television
- satellite communications (P7.10)
• recall the nature of radio waves and understand how interference affects the quality of the received signals (P7.11)
• recall that transmitted radio waves can reach the receiver as ground, sky or space waves and recall the typical frequency ranges associated with these waves (P7.12)
• describe, by suitable diagrams, ground waves, sky waves and space waves (P7.13)
• recall the part played by the ionosphere in reflecting radio waves (P7.14)
• understand the importance of diffraction of radio waves, including by buildings, mountains, curvature of the Earth and transmission dishes (P7.15)
• understand that the amount of diffraction depends upon wavelength and physical dimensions involved (P7.16)
• recall and use the relationships between wave speed (v), frequency (f) and wavelength (?)
f
? v
?
v = f ×? f = v = (P7.17)
• recall that amplitude modulation (AM) and frequency modulation (FM) are used in radio communications and understand the difference between them (P7.18)
• recall that AM signals have a greater range and are more susceptible to noise than FM signals (P7.19)

Satellites
Candidates will be assessed on their ability to:
• recall the difference between passive and active satellites (P7.20)
• describe the different uses for satellite communications systems including telephone and television communications, surveillance and monitoring, navigation
(P7.21)
• understand the features of a geostationary orbit and explain the importance to telecommunications of geostationary satellites (P7.22)
• understand the connection between the Earth’s spin and the use of monitoring satellites placed in low polar orbits (P7.23)
• use the quantitative relationship between orbital speed, orbital radius and time period:
time period
2 orbital radius
orbital speed
p ×
=
T
v = 2× p × r
(P7.24)
• understand the role of the gravitational force of the Earth as the centripetal force on the satellite (P7.25)
• use the quantitative relationship between the force acting on a satellite, mass (m), orbital speed (v) and radius (r):
( )
radius
force mass orbital speed
= × 2 F m v
r
=
× 2
(P7.26)

P8: Particles
• Units
• Ideal gas molecules
• Atoms and nuclei
• Electrons and other particles
Units
Candidates will be assessed on their ability to:
• use the following units: kelvin (K), coulomb (C), ampere (A), volt (V), joule (J), pascal (Pa), speed (m/s) (P8.01)
Ideal gas molecules
Candidates will be assessed on their ability to:
• understand that there is an absolute zero of temperature which is –273 oC (P8.02)
• describe the kelvin scale of temperature and be able to convert between the kelvin and Celsius scales (P8.03)
• understand that an increase in temperature results in an increase in speed of gas particles and that the kelvin temperature of the gas is proportional to their average kinetic energy (P8.04)
• explain the pressure exerted by a gas in terms of the motion of its molecules (P8.05)
• describe the qualitative relationship between pressure and kelvin temperature for a gas in a sealed container (P8.06)
• use the quantitative relationship between the pressure and the kelvin temperature:
2
2
1
1
T
P
T
P
= (P8.07)

Atoms and nuclei
Candidates will be assessed on their ability to:
• describe the results of Geiger and Marsden’s experiments with gold foil and alpha particles (P8.08)
• describe Rutherford’s nuclear model of the atom and how it accounts for the results of Geiger and Marsden’s experiment and understand the factors (charge and speed) which affect the deflection of alpha particles by a nucleus (P8.09)
• recall the qualitative features of the curve obtained when the number of neutrons (N) is plotted against the number of protons (Z) for stable isotopes (P8.10)
• understand that if an isotope does not lie on this curve it will be unstable and radioactive (P8.11)
• recall that an isotope that lies above the curve has too many neutrons to be stable and will undergo ß– decay (emit an electron) (P8.12)
• understand that in the process of ß– decay a neutron becomes a proton plus an electron (P8.13)
• recall that an isotope that lies below the curve has too few neutrons to be stable and will undergo ß+ decay (emit a positron) (P8.14)
• understand that in the process of ß+ decay a proton becomes a neutron plus a positron (P8.15)
• describe the effects on the proton (atomic) and mass numbers of a nucleus of ß– and ß+ decay (P8.16)
• recall that nuclei with greater than 82 protons usually undergo a decay (P8.17)
• recall that as a result of ß– or ß+decay nuclei often undergo rearrangement with a loss of energy as ? radiation (P8.18)
• understand that a nucleus of U-235 can be split (fission) by collision with a neutron and that this process releases energy in the form of kinetic energy of the fission products (P8.19)
• recall that the fission of U-235 produces two daughter nuclei and a small number of neutrons (P8.20)
• understand that a chain reaction can be set up if the neutrons produced by one fission strike other U-235 nuclei (P8.21)
• describe in outline how the fission process can be used as an energy source to generate electricity (P8.22)
• understand that the products of nuclear fission are radioactive and the implications this has for their safe storage over long periods (P8.23)

Electrons and other particles
Candidates will be assessed on their ability to:
• recall that the electron is a fundamental, negatively charged particle (P8.24)
• recall that the proton and neutron are not fundamental particles but each contains three particles called quarks (P8.25)
• recall that the positron is a fundamental, positively charged particle with the same mass as the electron (P8.26)
• recall that there are two types of quark in protons and neutrons and that ß decay occurs when one quark changes to the other type, which in turn causes the neutron to become a proton (ß– decay) or the proton to become a neutron (ß+ decay) (P8.27)
• understand that electrons are ‘boiled off’ hot metal filaments and this is called thermionic emission (P8.28)
• understand the principles of a simple electron gun with a heated cathode and accelerating anode (P8.29)
• use the quantitative relationship between kinetic energy gained, electronic charge and accelerating voltage:
kinetic energy = electronic charge × accelerating voltage KE = e × V (P8.30)

• recall that a beam of electrons is equivalent to an electric current and perform simple calculations involving the rate of flow of electrons and the current, given the electronic charge (P8.31)
• understand that an electron beam, or a stream of charged ink drops, can be deflected by the electric field between parallel charged metal plates (P8.32)
• understand the principal uses of electron beams, including:
- TV picture tubes
- computer monitors
- oscilloscopes
- the production of X-rays (P8.33)
• understand how an oscilloscope can be used to measure voltage and frequency (P8.34)

Specification