oxford aqa as physics

• 3.1.1 USE OF SI UNITS AND THEIR PREFIXES Fundamental (base) units. Use of mass, length, time, amount of substance, temperature, electric current and their associated SI units. SI units derived. Knowledge and use of the SI prefixes (T, G, M, k, c, m, μ, n, p, f), values and standard form. The fundamental unit of light intensity, the candela, is not required. Students are not expected to recall definitions of the fundamental quantities. Dimensional analysis is not required. Students should be able to convert between different units of the same quantity, eg J and eV, J and kW h.
• 3.1.2 LIMITATION OF PHYSICAL MEASUREMENTS Identification and suggestions for removal of random and systematic errors. Precision, repeatability, reproducibility, resolution and accuracy. Use of absolute, fractional and percentage uncertainties to represent uncertainty in the final answer for a quantity. Combination of absolute and percentage uncertainties where measurements are added, subtracted, multiplied, divided, or raised to powers. Combinations involving trigonometric or logarithmic functions will not be required. Representation of uncertainty in a data point on a graph using error bars. Determine the uncertainties in the gradient and intercept of a straight-line graph for graphs with or without associated error bars. In practical work students should understand the link between the number of significant figures in the value of a quantity and its associated uncertainty.
• 3.1.3 ESTIMATION OF PHYSICAL QUANTITIES Estimation of approximate values of physical quantities to the nearest order of magnitude. Use of these estimates together with their knowledge of physics to produce further derived estimates also to the nearest order of magnitude.

Vectors and their treatment are introduced followed by development of the student’s knowledge and understanding of forces, energy and momentum. A study of materials is considered in terms of their bulk properties including elastic and plastic behaviour, the Young modulus and tensile strength.

• 3.2.1 SCALARS AND VECTORS Nature of scalars and vectors. Examples should include: velocity/speed, mass, force/weight, acceleration, displacement/distance. Addition of vectors by calculation or scale drawing. Conditions for equilibrium for two or three coplanar forces acting at a point. Appreciation that objects at rest or moving with constant velocity are in equilibrium.
• 3.2.2 MOMENTS Moment of a force about a point. Moment defined as force × perpendicular distance from the point to the line of action of the force. Couple as a pair of equal and opposite coplanar forces. Moment of couple defined as force × perpendicular distance between the lines of action of the forces. Principle of moments. Centre of mass. Knowledge that the position of the centre of mass of uniform regular solid is at its centre.
• 3.2.3 MOTION ALONG A STRAIGHT LINE Displacement, speed, velocity, acceleration. v = ∆s/∆t a = ∆v/∆t Calculations may include average and instantaneous speeds and velocities. Representation by graphical methods of uniform and non-uniform acceleration eg motion of a bouncing ball. Significance and calculation of areas in velocity–time and acceleration–time graphs. Significance and calculation of gradients in displacement–time and velocity–time graphs. Equations for uniform acceleration: v = u + at s = ( u + v )t s = u t + 1 at 2 v 2 = u 2 + 2as 22 Acceleration due to gravity, g

• Required practical 1 Determination of g by a freefall method. Procedures should include determination of g from graph (eg from graph of s against t2)

• 3.2.4 PROJECTILE MOTION Independent effect of motion in horizontal and vertical directions of a uniform gravitational field. Problems will be solvable using the equations of uniform acceleration. Qualitative treatment of friction. Distinctions between static and dynamic friction will not be tested. Qualitative treatment of lift force and drag force. Terminal speed. Knowledge that air resistance increases with speed. Qualitative understanding of the effect of air resistance on the trajectory of a projectile and on the factors that affect the maximum speed of a vehicle.
• 3.2.5 NEWTON’S LAWS OF MOTION Knowledge and application of the three laws of motion. Use of F = ma in situations where the mass is constant.
• 3.2.6 MOMENTUM momentum = mass × velocity; p = mv Conservation of linear momentum. Principle applied quantitatively to problems in one dimension. Elastic and inelastic collisions; explosions. Force as the rate of change of momentum, F = ∆(mv)/∆t Impulse = change in momentum. F∆t = ∆mv , where F is constant. Significance of the area under a force–time graph. Quantitative questions may be set on forces that vary with time. Relationship between impact forces and contact times (eg kicking a football, crumple zones, packaging).
• 3.2.7 WORK, ENERGY AND POWER Energy transferred, W = Fs cos θ where θ is the angle between F and s Significance of the area under a force–displacement graph. Power = rate of doing work = rate of energy transfer, P = ∆W∆t = Fv Quantitative questions may be set on variable forces. Efficiency = useful output power input power Efficiency may be expressed as a percentage.
• 3.2.8 CONSERVATION OF ENERGY Principle of conservation of energy. ∆Ep =mg∆h and Ek = 12mv2 Quantitative and qualitative application of energy conservation to examples involving gravitational potential energy, kinetic energy, elastic potential energy and work done against resistive forces.
• 3.2.9 BULK PROPERTIES OF SOLIDS Density ρ = m/V Hooke’s law, elastic limit. F = k∆L, k as either stiffness and spring constant. Tensile strain and tensile stress. Elastic strain energy, breaking stress. energy stored = 1/2F ∆L^2 = area under force−extension graph Description of plastic behaviour, fracture and brittle behaviour, linked to force–extension graphs. Quantitative and qualitative application of energy conservation to examples involving elastic strain energy and energy to deform. Elastic potential energy in spring transformed to kinetic and gravitational potential energy. Interpretation of simple stress–strain curves.
• 3.2.10 THE YOUNG MODULUS Young modulus E = tensile stress = F/A tensile strain ∆L/L Use of stress−strain graphs to determine the Young modulus.

• Required practical 2 Investigation of load-extension graph for a wire and determination of the Young modulus for the material of the wire.

In this section students will study microscopic nature of matter and the basics of radioactive decay. They will gain an appreciation of the range of elementary particles and their interactions.

• 3.3.1 CONSTITUENTS OF THE ATOM Simple model of the atom, including the proton, neutron and electron. Evidence for a nucleus: Rutherford scattering. Appreciation of how knowledge and understanding of the structure of the nucleus has changed over time. Charge and mass of the proton, neutron and electron in SI units and relative units. Use of the atomic mass unit (amu) is not required at International AS (see Section 3.12.2). Specific charge of the proton and the electron, and of nuclei and ions. Proton number Z, nucleon number A, nuclide notation. Students should be familiar with the ZA X notation.
• 3.3.2 ELEMENTARY PARTICLES Classification of particles: For every type of particle, there is a corresponding antiparticle. Students should know that the positron, antiproton, antineutron and antineutrino are the antiparticles of the electron, proton, neutron and neutrino respectively. Knowledge of annihilation and pair production and the energies involved. Comparison of particle and antiparticle masses, charge and rest energy in MeV. The use of E = mc2 is not required in calculations.
• 3.3.3 RADIOACTIVITY Possible decay modes of unstable nuclei including α, β−, β+ Equations for α, β−, β+ decays including neutrinos and antineutrinos. The existence of the neutrino was hypothesised to account for conservation of momentum and energy in beta decay. The decay of a free neutron should be known.

Half-life; Determination of half-life from graphical decay data including decay; Simple calculations involving times that are whole numbers of the half-life. Use of equations for exponential decay will be required at International A2 only, (see Section 3.9). Existence of nuclear excited states; γ ray emission; application eg use of technetium-99m as a source in medical diagnosis. Properties of α, β, and γ radiation and experimental identification of these using simple absorption experiments; applications eg to relative hazards of exposure to humans. Applications also include thickness measurements of aluminium foil, paper and steel. Inverse-square law for γ radiation: I = I o r2 Experimental verification of inverse-square law. Applications eg to safe handling of radioactive sources. Background radiation; examples of its origins and experimental elimination from calculations.

This section builds on, and develops, knowledge and understanding of electricity from prior study. It provides opportunities for the development of practical skills and lays the groundwork for later study of the many electrical applications that are important to society.

• 3.4.1 BASICS OF ELECTRICITY Electric current as the rate of flow of charge; potential difference as work done per unit charge. I=∆Q V=W ∆t Q Resistance defined as R = VI
• 3.4.2 CURRENT–VOLTAGE CHARACTERISTICS Characteristics for an ohmic conductor, semiconductor diode, and filament lamp. Ohm’s law as a special case where I ∝ V under constant physical conditions. Unless specifically stated in questions, ammeters and voltmeters should be treated as ideal (having zero and infinite resistance respectively). Questions can be set where either I or V is on the horizontal axis of the characteristic graph.
• 3.4.3 RESISTIVITY Resistivity ρ = RA L Description of the qualitative effect of temperature on the resistance of metal conductors and thermistors. Only negative temperature coefficient (ntc) thermistors will be considered.

Applications of thermistors to include temperature sensors and resistance–temperature graphs. Superconductivity as a property of certain materials which have zero resistivity at and below a critical temperature which depends on the material. Applications of superconductors to include the production of strong magnetic fields and the reduction of energy loss in transmission of electric power. Critical field will not be assessed.

• 3.4.4 CIRCUITS Resistors: in series, R T = R 1 + R 2 + R 3 +… in parallel, 1/Rt = 1/R1 + 1/R2 + 1/R3 + Energy and power equations: E = IVt; P = IV = I 2 R = V 2 R The relationships between current, voltage and resistance in series and parallel circuits, including cells in series and identical cells in parallel. Conservation of charge and conservation of energy in dc circuits.
• 3.4.5 POTENTIAL DIVIDER The potential divider used to supply constant or variable potential difference from a power supply. The use of the potentiometer as a measuring instrument is not required. Examples should include the use of variable resistors, thermistors, and light dependent resistors (LDR) in the potential divider.
• 3.4.6 ELECTROMOTIVE FORCE AND INTERNAL RESISTANCE emf: ε=QE; ε=I(R+r) Effect of internal resistance on terminal pd. Students will be expected to understand and perform calculations for circuits in which the internal resistance of the supply is not negligible.

• Required practical 3 Investigation of the emf and internal resistance of electric cells and batteries by measuring the variation of the terminal pd of a cell or battery with current.

The earlier study of mechanics is developed further with a study of examples of systems undergoing oscillations. This is followed by a study of the characteristics, properties, and applications of travelling waves and stationary waves and concludes with a study of refraction, diffraction, superposition and interference. They will also study evidence for wave-particle duality of electromagnetic radiation and moving particles.

• 3.5.1 OSCILLATING SYSTEMS Mass-spring system: T = 2π sqrt(m/k) Simple pendulum: T = 2π sqrt(l/g) Variation of Ek , Ep , and total energy with both displacement and time. Effects of damping on oscillations.

• Required practical 4 Investigation into simple harmonic systems using a mass-spring system and a simple pendulum.

• 3.5.2 FORCED VIBRATIONS AND RESONANCE Qualitative treatment of free and forced vibrations. Resonance and the effects of damping on the sharpness of resonance. Examples of these effects in mechanical systems and situations involving stationary waves.
• 3.5.3 PROGRESSIVE WAVES Oscillation of the particles of the medium; amplitude, frequency, wavelength, speed, phase, phase difference, c = f λ f = 1 T Phase difference measured as angles (radians or degrees) or as fractions of a cycle.
• 3.5.4 LONGITUDINAL AND TRANSVERSE WAVES Nature of longitudinal and transverse waves. Examples to include: sound, electromagnetic waves, and waves on a string. Students will be expected to know the direction of displacement of particles/fields relative to the direction of energy propagation and that all electromagnetic waves travel at the same speed in a vacuum. Use of ultrasound in medicine. Polarisation as evidence for the nature of transverse waves. Applications of polarisers to include Polaroid material and the alignment of aerials for transmission and reception. Malus’s law will not be expected.
• 3.5.5 PRINCIPLE OF SUPERPOSITION OF WAVES AND FORMATION OF STATIONARY WAVES Stationary waves. Nodes and antinodes on strings. f = 1 T for the first harmonic 2l μ The formation of stationary waves by two waves of the same frequency travelling in opposite directions. A graphical explanation of formation of stationary waves will be expected. Stationary waves formed on a string and those produced with microwaves and sound waves should be considered. Stationary waves on strings will be described in terms of harmonics. The terms fundamental (for first harmonic) and overtone will not be used. Knowledge of experiments that investigate the variation of the frequency of stationary waves on a string with length, tension and mass per unit length of the string.
• 3.5.6 INTERFERENCE Path difference. Coherence. Interference and diffraction using a laser as a source of monochromatic light. Young’s double-slit experiment: the use of two coherent sources or the use of a single source with double slits to produce an interference pattern. Fringe spacing w = λsD Production of interference pattern using white light. Students are expected to show awareness of safety issues associated with using lasers. Students will not be required to describe how a laser works. Students will be expected to describe and explain interference produced with sound and electromagnetic waves.

• Required practical 5 Investigation of interference effects to include the Young’s slit experiment and interference by a diffraction grating.

• 3.5.7 DIFFRACTION Appearance of the diffraction pattern from a single slit using monochromatic and white light. Qualitative treatment of the variation of the width of the central diffraction maximum with wavelength and slit width. The graph of intensity against angular separation is not required. Plane transmission diffraction grating at normal incidence. Derivation of d sinθ = nλ Use of the spectrometer will not be tested. Applications of diffraction gratings.
• 3.5.8 REFRACTION AT A PLANE SURFACE Refractive index of a substance, n = c s Students should recall that the refractive index of air is approximately 1. Snell’s law of refraction for a boundary n1sin θ1 = n2sin θ2 Total internal reflection sinθc = n12 Simple treatment of fibre optics including the function of the cladding. Optical fibres will be limited to step index only. Material and modal dispersion. Students are expected to understand the principles and consequences of pulse broadening and absorption.
• 3.5.9 COLLISIONS OF ELECTRONS WITH ATOMS Ionisation and excitation; understanding of ionisation and excitation in the fluorescent tube. The electron volt. Line spectra (eg of atomic hydrogen) as evidence for transitions between discrete energy levels in atoms. h f = E1 – E2 Characteristic and line spectrum for X-rays and use of X-rays in medical applications. Students should know the basic structure and operation of an X-ray tube. In questions energy levels may be given in eV or J. Students will be expected to be able to convert eV into J and vice versa.
• 3.5.10 PHOTOELECTRIC EFFECT Photon model of electromagnetic radiation, the Planck constant. E =hf = hc λ Photoelectric effect: threshold frequency; photon explanation of threshold frequency. Work function φ, stopping potential. Photoelectric equation: h f = φ + Ek (max) Ek (max) is the maximum kinetic energy of the photoelectrons. The experimental determination of stopping potential is not required.
• 3.5.11 WAVE PARTICLE DUALITY Students should know that electron diffraction suggests that particles possess wave properties and the photoelectric effect suggests that electromagnetic waves have a particulate nature. Details of particular methods of particle diffraction are not expected. de Broglie equation λ = h where mv is the momentum. Students should be able to explain how and why the amount of diffraction changes when the momentum of the particle is changed. Appreciation of how knowledge and understanding of the nature of matter changes over time.

• 3.6.1 CIRCULAR MOTION Motion in a circle at constant speed implies an acceleration and the need for a centripetal force. Angular speed ω = vr = 2πf Centripetal acceleration a = v2 = ω2r Centripetal force F = mv 2 = mω2r r v2 The derivation of a = r will not be examined.
• 3.6.2 SIMPLE HARMONIC MOTION Characteristic features of simple harmonic motion Condition for SHM: a = − ω2 x x=Acosωtandv=±ω (A2−x2) Graphical representations linking x, v, a and t. Velocity as gradient of the displacement time graph. Acceleration as the gradient of the velocity time graph.

Maximum speed = ωA Maximum acceleration = ω2A Derivation of formulae for the period of a mass-spring system and a simple pendulum T = 2 π mk T = 2 π gl Graphs of variation of Ek, Ep and total energy with displacement, and with time Total energy of the oscillator = 12 mω2 A2

• 3.7.1 NEWTON’S GRAVITATIONAL LAW Gravity as a universal attractive force acting between all matter. Force between point masses F = Gm1m2 where G is the gravitational constant r2
• 3.7.2 GRAVITATIONAL FIELD STRENGTH Concept of a force field as a region in which a body experiences a force. Representation by gravitational field lines g as force per unit mass defined by g = mF Magnitude of g in a radial field given by g = GM r2
• 3.7.3 GRAVITATIONAL POTENTIAL Understanding of definition of gravitational potential including zero potential at infinity and gravitational potential difference. Work done in moving mass: ∆W = m∆v Gravitational potential in a radial field: V = − GrM Equipotential surfaces: appreciation that no work is done when moving a mass along an equipotential surface. Graphical representations of the variations of g and V with r V related to g by g = − ∆V ∆r
• 3.7.4 ORBITS OF PLANETS AND SATELLITES Orbital period and speed related to radius of circular orbit. Energy considerations for an orbiting satellite. Significance of a geosynchronous orbit.

• 3.8.1 COULOMB’S LAW Force between point charges in a vacuum: F = 1 Q1Q2 where ε is the permittivity of free space. 4πεo r2 o Appreciation that air can be treated as a vacuum when calculating force between charges. For a charged sphere, charge may be considered to be at the centre. Comparison of magnitude of gravitational and electrostatic forces between subatomic particles.
• 3.8.2 ELECTRIC FIELD STRENGTH Representation of electric fields by electric field lines. Electric field strength E as force per unit charge defined by E = QF Magnitude of E in a uniform field: E = dV Derivation from work done moving charge between plates: Fd = QΔV Trajectory of moving charged particle entering a uniform electric field initially at right angles. Magnitude of E in a radial field given by E = 1 Q 4πεo r2
• 3.8.3 ELECTRIC POTENTIAL Understanding of definition of absolute electric potential, including zero value at infinity, and of electric potential difference. Work done in moving charge Q given by ∆ W = Q ∆ V Equipotential surfaces. Appreciations that no work is done moving charge along an equipotential surface. Magnitude of V in a radial field given by V = 1 Q 4πεo r Graphical representations of variations of E and V with r. V related to E by E = ∆V ∆r ∆V from the area under graph of E against r.
• 3.8.4 CAPACITORS Definition of capacitance: C = VQ For a parallel plate capacitor: C = Aεo εr / d Relative permittivity and dielectric constant. Dielectric action in a capacitor: Students should be able to describe the action of a simple polar molecule that rotates in the presence of an electric field. Energy stored from area under a graph of charge against pd: E = 1/2QV = 1/2CV2 = 1/2 Q2/C

• 3.9.1 CAPACITOR CHARGE AND DISCHARGE Graphical representation of charging and discharging of capacitors through resistors. Corresponding graphs for Q, V and I against time for charging and discharging. Interpretation of gradients and areas under graphs where appropriate. Time constant = RC Calculation of time constants including their determination from graphical data. Time to halve, T 1⁄2 = ln 2RC RC Quantitative treatment of capacitor discharge, Q = Qo e^(−t/RC) Use of the corresponding equations for V and I Quantitative treatment of capacitor charge Q = Qo (1 − e^(-t/RC))

• Required practical 6 Investigation of the charge and discharge of capacitors. Analysis techniques should include log-linear plotting leading to a determination of the time constant, RC.

• 3.9.2 EXPONENTIAL CHANGES IN RADIOACTIVITY Random nature of radioactive decay; constant decay probability of a given nucleus; ∆N =−λN; N=Noe−λt ∆t Use of activity, A = λN Modelling with constant decay probability. Questions may be set which require students to use A = Aoe−λt Questions may also involve use of molar mass or the Avogadro constant. Half-life equation T1/2 = ln2 λ Determination of half-life from graphical decay data including decay curves and log graphs.

• 3.10.1 MAGNETIC FLUX DENSITY Force on a current-carrying wire in a magnetic field: F = BIL when field is perpendicular to current. Fleming’s left hand rule. Magnetic flux density B and definition of the tesla.
• 3.10.2 MOVING CHARGES IN A MAGNETIC FIELD Force on charged particles moving in a magnetic field: F = BQv when the field is perpendicular to velocity. Direction of force on positive and negative charged particles. Circular path of particles; application in devices such as the cyclotron.
• 3.10.3 MAGNETIC FLUX AND FLUX LINKAGE Magnetic flux defined by Φ = BA where B is perpendicular to A. Flux linkage as NΦ where N is the number of turns. Flux and flux linkage passing through a rectangular coil rotated in a magnetic field: Flux linkage NΦ = BANcosθ
• 3.10.4 ELECTROMAGNETIC INDUCTION Simple experimental phenomena. Faraday’s and Lenz’s laws. Magnitude of induced emf = rate of change of flux linkage: ε = ∆Φ ∆t Applications such as a straight conductor moving in a magnetic field. Production of eddy currents. Emf induced in a coil rotating uniformly in a magnetic field: ε = BANω sin ωt
• 3.10.5 ALTERNATING CURRENTS Sinusoidal voltages and currents only; root mean square, peak and peak-to-peak values for sinusoidal waveforms only. Irms=Io ;Vrms=Vo 22 Application to the calculation of mains electricity peak and peak-to-peak voltage values. Use of an oscilloscope as a dc and ac voltmeter, to measure time intervals and frequencies, and to display ac waveforms. No details of the structure of an oscilloscope are required but familiarity with the operation of the controls is expected.
• 3.10.6 THE OPERATION OF A TRANSFORMER The transformer equation N s = Vs pp Transformer efficiency = ISVS IPVP Causes of in efficiencies in a transformer. Transmission of electrical power at high voltage including calculations of power and voltage losses in transmission lines.

• Required practical 7 Investigation of the efficiency of a transformer.

In Sections 3.11 – 3.13, students will study alternative energy sources. They must be able to use their knowledge of the advantages and disadvantages of each to make a judgment of appropriate sources to be used in different situations. The latter parts of this section brings together ideas from other parts of the specification.

• 3.11.1 ENERGY TRANSFER BY HEATING AND DOING WORK Internal energy is the sum of the randomly distributed kinetic energies and potential energies of the particles in a body. The internal energy of a system is increased when energy is transferred to it by heating or when work is done on it (and vice versa). The first law of thermodynamics: ΔU = Q + W where Q is the energy input to the system by heating and W is the work done ON the system. Appreciation that during a change of state the potential energies of the particle ensemble are changing but not the kinetic energies. Calculations involving transfer of energy including continuous flow systems: For a change of temperature: Q = mc Δθ where c is specific heat capacity. For a change of state Q = ml where l is the specific latent heat.

• Required practical 8 Determination of specific heat capacity by an electrical method.

• 3.11.2 ENERGY TRANSFER BY CONDUCTION Rate of energy transfer by conduction = kAL∆θ/L where k is the thermal conductivity. Use of U–values to calculate energy losses for parallel surfaces only. Rate of energy transfer = UA ∆θ where U = L/k
• 3.11.3 IDEAL GASES Gas laws as experimental relationships between p, V, T and the mass of the gas. Concept of absolute zero of temperature. Ideal gas equation: pV = nRT for n moles and pV = N kT for N molecules. Work done = p∆V Avogadro constant NA, molar gas constant R, Boltzmann constant k Molar mass and molecular mass.

• Required practical 9 Investigation of Boyle’s law (constant temperature) and Charles’s law (constant pressure) for a gas.

• 3.11.4 KINETIC THEORY OF GASES Brownian motion as evidence for existence of atoms. Explanation of relationships between p, V and T in terms of a simple molecular model. Students should understand that the gas laws are empirical in nature whereas the kinetic theory model arises from theory. Assumptions leading to pV = 1/3 Nm (crms )^2 : Calculations using the formula are expected. Appreciation that for an ideal gas, internal energy is kinetic energy of the atoms. Use of average molecular kinetic energy = 1/2 m (crms )^2 = 3/2 kT = 3/2 RT/NA

• 3.12.1 RADIUS OF THE NUCLEUS Estimate of radius from closest approach of alpha particles and determination of radius from electron diffraction. Knowledge of typical values for nuclear radius. Students will need to be familiar with the Coulomb equation for the closest approach estimate. Dependence of radius on nucleon number: R = Ro A1/3 derived from experimental data. Interpretation of equation as evidence for constant density of nuclear material. Calculation of nuclear density. Students should be familiar with the graph of intensity against angle for electron diffraction by a nucleus.
• 3.12.2 MASS AND ENERGY Appreciation that E = mc 2 applies to all energy changes. Simple calculations involving mass difference, binding energy and mass defect. Atomic mass unit, u. Conversion of units; 1 u = 931.5 MeV. Fission and fusion processes. Simple calculations from nuclear masses of energy released in fission and fusion reactions. Graph of average binding energy per nucleon against nucleon number. Students may be expected to identify, on the plot, the regions where nuclei will release energy when undergoing fission/fusion.
• 3.12.3 INDUCED FISSION Fission induced by thermal neutrons; possibility of a chain reaction; critical mass. The functions of the moderator, control rods, and coolant in a thermal nuclear reactor. Details of particular reactors are not required. Students should have studied a simple mechanical model of moderation by elastic collisions. Factors affecting the choice of materials for the moderator, control rods and coolant. Examples of materials used for these functions.
• 3.12.4 SAFETY ASPECTS NUCLEAR REACTORS Fuel used, remote handling of fuel, shielding, emergency shut-down. Production, remote handling, and storage of radioactive waste materials. Appreciation of balance between risk and benefits in the development of nuclear power.
• 3.12.5 NUCLEAR FUSION Knowledge of suitable nuclei for use in a fusion reactor. Estimation of kinetic energy of nuclei necessary for fusion to take place and of the temperature of the plasma. Energy release from fusion of two nuclei. Solar fusion cycle limited to the hydrogen cycle. Appreciation of the problems that have to be overcome to produce a practical nuclear reactor.

• 3.13.1 ROTATIONAL MOTION I = mr2 for a point mass. I = Σ mr2 for an extended object. Qualitative knowledge of the factors that affect the moment of inertia of a rotating object. Expressions for moment of inertia will be given where necessary. Angular displacement, angular speed, angular velocity and angular acceleration. Equations for uniform angular acceleration ω=ωo+αt θ=(ω0 +ω)t θ=ω0t+1αt2 ω2 =ωo2 +2αθ 22 Torque = Fr = Iα Angular momentum Iω Conservation of angular momentum Rotational kinetic energy Ek( rot ) = 12 Iω2 Work W=Tθ and power P = Tω Students should be aware of the analogy between rotational and translational dynamics.
• 3.13.2 WIND ENERGY Maximum power available from a wind turbine E = 12 πr2 ρv3 where ρ is the density of air. Appreciation why all this energy cannot be used. Wind shadows determine arrangement of turbines in a wind farm. Environmental factors in the use of wind turbines.
• 3.13.3 SOLAR ENERGY Intensity of energy from the Sun at the Earth’s surface. Use of inverse square law to determine intensity at different distances from the Sun: I = P 4πr2 V-I characteristic and maximum power for a solar cell. Arrangement of cells in solar arrays.

• Required practical 10 Investigation of the inverse square law for light using an LDR and a point source.

• 3.13.4 HYDROELECTRIC POWER AND PUMPED STORAGE Components of a hydroelectric power station: Turbine and generator. Transfer of gravitational potential energy to kinetic energy. Maximum power available from flow of water through a turbine E = 12 πr2 ρv3 where ρ is the density of water. Idea of base-power stations and back-up power stations. Principles of operation pumped storage systems.

• 6.2.1 PRACTICAL SKILLS Students should know how to:
  • use appropriate analogue apparatus to record a range of measurements (to include length/distance, temperature, pressure, force, angles, volume) and to interpolate between scale markings
  • use appropriate digital instruments, including electrical multimeters, to obtain a range of measurements (to include time, current, voltage, resistance, mass)
  • use methods to increase accuracy of measurements, such as timing over multiple oscillations, use of fiduciary marker, use of set square and plumb line
  • use stopwatch and light gates for timing
  • use calipers and micrometers for small distances, using digital and vernier scales
  • correctly construct circuits from circuit diagrams using DC power supplies, cells, and a range of circuit components, including those where polarity is important
  • design, construct and check circuits using DC power supplies, cells, and a range of circuit components
  • use signal generator and oscilloscope, including volts/division and time-base
  • generate and measure waves, using microphone and loudspeaker, ripple tank, vibration transducer and a microwave/radio wave source
  • use laser and light source to investigate characteristics of light, including interference and diffraction
  • use ICT for computer modelling and to process data
  • use data logger with sensors to collect data. Students should be able to:
    • design an experiment to test the relationship between two physical quantities
    • evaluate practical procedures and techniques and suggest improvements that would improve reliability.
• 6.2.2 DATA ANALYSIS SKILLS Plotting of labelled graphs with suitable scales and units. Comparison of data for a linear graph with the general formula y = mx + c ; determination of gradients and intercepts when a graph shows a true origin or a false origin. Appreciation that:
• a straight line graph through the origin with a positive gradient indicates that the quantities show direct proportionality
• a straight line graph with an intercept indicates that the quantities vary linearly with one another
• a graph with a negative gradient indicates that the quantities are indirectly proportional. Use of ratios to test power relationships INTERNATIONAL A2 ONLY Use of a log-log or ln–ln graph to determine the constants k and n in a relationship of the form y=kxn Use of a ln-linear graph to determine the constants k and n in a relationship of the form y = ke nx
• 6.1 REQUIRED PRACTICAL ACTIVITIES

• International AS practical activities Students must carry out the practical activities listed below. The International AS written papers test knowledge and understanding of the procedures involved and require evaluation of the techniques adopted. Students may need to interpret specimen results.

• Practical activity
  1. Determination of g by a freefall method. Procedures should include determination of g from graph (eg from graph of s against t 2).
  2. Investigation of load-extension graph for a wire and determination of the Young modulus for the material of the wire.
  3. Investigation of the emf and internal resistance of electric cells and batteries by measuring the variation of the terminal pd of a cell or battery with current.
  4. Investigation into simple harmonic systems using a mass-spring system and a simple pendulum.
  5. Investigation of interference effects to include the Young’s slit experiment and interference by a diffraction grating.
• International A2 practical activities Students must carry out the practical activities listed below. The International A2 written papers test knowledge and understanding of the procedures involved and require evaluation of the techniques adopted. Students may need to interpret specimen results.
  1. Investigation of the charge and discharge of capacitors. Analysis techniques should include log-linear plotting leading to a determination of the time constant, RC.
  2. Investigation of the efficiency of a transformer.
  3. Determination of specific heat capacity using an electrical method.
  4. Investigation of Boyle’s law (constant temperature) and Charles’s law (constant pressure).
  5. Investigation of the inverse square law for light using an LDR and a point source.