Welsh Board ASlevel Syllabus 

In the exam, you are expected to demonstrate and apply knowledge of: 

Motion, Energy, and Matter 

1. Basic Physics 

(a) 
The 6 essential base SI units (kg, m, s, A, mol, K); 

(b) 
representing units in terms of the 6 base SI units and their prefixes; 

(c) 
checking equations for homogeneity using units; 

(d) 
the difference between scalar and vector quantities and to give examples of each – displacement, velocity, acceleration, force, speed, time, density, pressure etc; 

(e) 
the addition and subtraction of coplanar vectors, and perform mathematical calculations limited to two perpendicular vectors; 

(f) 
how to resolve a vector into two perpendicular components; 

(g) 
the concept of density and how to use the equation:
to calculate mass, density and volume; 

(h) 
what is meant by the turning effect of a force; 

(i) 
the use of the principle of moments; 

(j) 
the use of centre of gravity, for example in problems including stability: identify its position in a cylinder, sphere and cuboid (beam) of uniform density; 

(k) 
when a body is in equilibrium the resultant force is zero and the net moment is zero, and be able to perform simple calculations. 

The Induction notes contain many of the skills, which, although not specified in the syllabus, are expected as a matter of course, both in written and experimental work. You are advised to read them. 
Induction  
2. Kinematics 

(a) 
What is meant by displacement, mean and instantaneous values of speed, velocity and acceleration; 

(b) 
the representation of displacement, speed, velocity and acceleration by graphical methods; 

(c) 
the properties of displacementtime graphs, velocitytime graphs, and interpret speed and displacementtime graphs for nonuniform acceleration; 

(d) 
how to derive and use equations which represent uniformly accelerated motion in a straight line; 

(e) 
how to describe the motion of bodies falling in a gravitational field with and without air resistance  terminal velocity; 

(f) 
the independence of vertical and horizontal motion of a body moving freely under gravity; 

(g) 
the explanation of the motion due to a uniform velocity in one direction and uniform acceleration in a perpendicular direction, and perform simple calculations 

3. Dynamics 

(a) 
The concept of force and Newton's 3rd law of motion; 

(b) 
how free body diagrams can be used to represent forces on a particle or body; 

(c) 
the use of the relationship ΣF = ma in situations where mass is constant; 

(d) 
the idea that linear momentum is the product of mass and velocity; 

(e) 
the concept that force is the rate of change of momentum, applying this in situations where mass is constant; 

(f) 
the principle of conservation of momentum and use it to solve problems in one dimension involving elastic collisions (where there is no loss of kinetic energy) and inelastic collisions (where there is a loss of kinetic energy). 

4. Energy Concepts 

(a) 
The idea that work is the product of a force and distance moved in the direction of the force when the force is constant; 

(b) 
the calculation of the work done for constant forces, when the force is not along the line of motion (work done = Fx cos q ); 

(c) 
the principle of conservation of energy including knowledge of gravitational potential energy (mgDh), elastic potential energy (½ kx^{2}) and kinetic energy (½ mv^{2}); 

(d) 
The workenergy relationship: ; (Note that the physics code s is used for distance in the notes) 

(e) 
power being the rate of energy transfer; 

(f) 
dissipative forces for example, friction and drag cause energy to be transferred from a system and reduce the overall efficiency of the system; 

(g) 
Equation: . 

5. Solids Under Stress 

(a) 
Hooke’s law and use F = kx where the spring constant k is the force per unit extension; 
Materials 2 
(b) 
the ideas that for materials the tensile stress:
the tensile strain:
and the Young modulus:
when Hooke's Law applies;


(c) 
the work done in deforming a solid being equal to the area under a forceextension graph, which is 1/2 Fx if Hooke’s law is obeyed; 

(d) 
the classification of solids as crystalline, amorphous (to include glasses and ceramics) and polymeric; 
Materials 1 
(e) 
the features of a
forceextension (or stressstrain) graph for a metal such as

Materials 3 
(f) 
the features of a forceextension (or stressstrain) graph for a brittle material such as glass, to include:


(g) 
the features of a forceextension (or stressstrain) graph for rubber, to include:


6. Using Radiation to Investigate Stars 

(a) 
The idea that the stellar spectrum consists of a continuous emission spectrum, from the dense gas of the surface of the star, and a line absorption spectrum arising from the passage of the emitted electromagnetic radiation through the tenuous atmosphere of the star 
Astrophysics 5 
(b) 
the idea that bodies which absorb all incident radiation are known as black bodies and that stars are very good approximations to black bodies; 

(c) 
the shape of the black body spectrum and that the peak wavelength is inversely proportional to the absolute temperature (defined by T (K) = θ (°C) + 273.15); 

(d) 
Wien's displacement law, Stefan's law and the inverse square law to investigate the properties of stars – luminosity, size, temperature and distance [N.B. stellar brightness in magnitudes will not be required]; 

(e) 
the meaning of multiwavelength astronomy and that by studying a region of space at different wavelengths (different photon energies) the different processes which took place there can be revealed; 
Astrophysics 3 
7. Particles and Nuclear Structures 

(a) 
The idea that matter is composed of quarks and leptons and that there are three generations of quarks and leptons, although no questions will be set involving second or third generations:

Particles 7 (Leptons) (Quarks) 
(b) 
the idea that antiparticles exist for the particles given in the table above, that the properties of an antiparticle are identical to those of its corresponding particle apart from having opposite charge, and that particles and antiparticles annihilate; 
Particles 6 
(c) 
symbols for a positron and for antiparticles of quarks and hadrons; 

(d) 
the idea that quarks and antiquarks are never observed in isolation, but are bound into composite particles called hadrons, or three types of baryon (combinations of 3 quarks), or antibaryons (combinations of 3 antiquarks) or mesons (quarkantiquark pairs); 
Particles 9 (Mesons) (Baryons) 
(e) 
the quark compositions of the neutron and proton; 
Particles 10 
(f) 
how to use data in the table above to suggest the quark makeup of less well known first generation baryons and of charged pions; 
Particles 9 
(g) 
the properties of the four forces or interactions experienced by particles as summarized in the table below:

Particles 5 
(h) 
how to apply conservation of charge, lepton number and baryon number (or quark number) to given simple reactions; 
Particles 11 
(i) 
the idea that neutrino involvement and quark flavour changes are exclusive to weak interactions. 

Electricity and Light 

1. Conduction of Electricity 

(a) 
The fact that the unit of charge is the coulomb (C), and that an electron's charge, e, is a very small fraction of a coulomb; 
Electricity 1 
(b) 
the fact that charge can flow through certain materials, called conductors; 
Electricity 4 
(c) 
electric current being the rate of flow of charge; 
Electricity 1 
(d) 
the use of the equation: ; 

(e) 
current being measured in ampères (A), where 1 A = 1 C s^{1}; 

(f) 
the mechanism of conduction in metals as the drift of free electrons; 
Electricity 4 
(g) 
the derivation and use of the equation I = nAve for free electrons. 

2. Resistance 

(a) 
The definition of potential difference; 
Electricity 1 
(b) 
the idea that potential difference is measured in volts (V) where V = J C^{1}; 

(c) 
the characteristics of I – V graphs for the filament of a lamp, and a metal wire at constant temperature; 
Electricity 3 
(d) 
Ohm's law, the equation V = IR and the definition of resistance; 
Electricity 2 
(e) 
resistance being measured in ohms (Ω), where Ω = V A^{1}; 
Electricity 1 
(f) 
the application of:

Electricity 5 
(g) 
collisions between free electrons and ions gives rise to electrical resistance, and electrical resistance increases with temperature; 
Electricity 4 
(h) 
the application of:
the equation for resistivity; 

(i) 
the idea that the resistance of metals varies almost linearly with temperature over a wide range; 
Electricity 2 
(j) 
the idea that ordinarily, collisions between free electrons and ions in metals increase the random vibration energy of the ions, so the temperature of the metal increases; 

(k) 
what is meant by superconductivity, and superconducting transition temperature; 
Electricity 4 
(l) 
the fact that most metals show superconductivity, and have transition temperatures a few degrees above absolute zero (–273 °C); 

(m) 
certain materials (high temperature superconductors) having transition temperatures above the boiling point of nitrogen (–196 °C); 

(n) 
some uses of superconductors for example, MRI scanners and particle accelerators. 

3. D C Circuits 

(a) 
The idea that the current from a source is equal to the sum of the currents in the separate branches of a parallel circuit, and that this is a consequence of conservation of charge; 
Electricity 7 
(b) 
the sum of the potential differences across components in a series circuit is equal to the potential difference across the supply, and that this is a consequence of conservation of energy; 

(c) 
potential differences across components in parallel are equal; 

(d) 
the application of equations for the combined resistance of resistors in series and parallel; 

(e) 
the use of a potential divider in circuits (including circuits which contain LDRs and thermistors); 
Electricity 6 
(f) 
what is meant by the emf of a source; 
Electricity 8 
(g) 
the unit of emf is the volt (V), which is the same as that of potential difference; 

(h) 
the idea that sources have internal resistance and to use the equation V = E – Ir; 

(i) 
how to calculate current and potential difference in a circuit containing one cell or cells in series. 
Electricity 1 
4. The Nature of Waves 

(a) 
The idea that a progressive wave transfers energy without any transfer of matter; 
Waves 1 
(b) 
the difference between transverse and longitudinal waves; 
Waves 2 
(c) 
the term polarisation; 

(d) 
the terms in phase and in antiphase; 
Waves 1 
(e) 
the terms displacement, amplitude, wavelength, frequency, period and velocity of a wave; 

(f) 
graphs of displacement against time, and displacement against position for transverse waves only; 
Waves 2 
(g) 
the equation c = fλ; 
Waves 1 
(h) 
the idea that all points on wavefronts oscillate in phase, and that wave propagation directions (rays) are at right angles to wavefronts. 

5. Wave Properties 

(a) 
Diffraction occurring when waves encounter slits or obstacles; 
Waves 8 
(b) 
the idea that there is little diffraction when λ is much smaller than the dimensions of the obstacle or slit; 

(c) 
the idea that if λ is equal to or greater than the width of a slit, waves spread as roughly semicircular wavefronts, but if λ is less than the slit width the main beam spreads through less than 180° 

(d) 
how two source interference occurs; 
Waves 7 
(e) 
the historical importance of Young’s experiment; 
Turning Points 3 
(f) 
the principle of superposition, giving appropriate sketch graphs; 
Waves 3 
(g) 
the path difference rules for constructive and destructive interference between waves from in phase sources; 
Waves 7 
(h) 
the use of: ; (Note that the terms w and s are used in the notes) 

(i) 
the derivation and use of d sin θ = nλ for a diffraction grating; 
Waves 8 
(j) 
the idea that for a diffraction grating a very small d makes beams (“orders”) much further apart than in Young’s experiment, and that the large number of slits makes the bright beams much sharper; 

(k) 
the idea that coherent sources are monochromatic with wavefronts continuous across the width of the beam and, (when comparing more than one source) with a constant phase relationship; 
Waves 7 
(l) 
examples of coherent and incoherent sources; 

(m) 
the idea that for two source interference to be observed, the sources must have a zero or constant phase difference and have oscillations in the same direction; 

(n) 
the differences between stationary and progressive waves; 
Waves 4 
(o) 
the idea that a stationary wave can be regarded as a superposition of two progressive waves of equal amplitude and frequency, travelling in opposite directions, and that the internodal distance is λ/2. 

6. Refraction of Light 

(a) 
the refractive index, n, of a medium being defined as c/v, in which v is the speed of light in the medium and c is the speed of light in a vacuum 
Waves 6 
(b) 
the use of the equations: n_{1}v_{1} = n_{2}v_{2} and n_{1} sin θ_{1} = n_{2} sin θ_{2} (regarded as Snell’s law); 

(c) 
how Snell's law relates to the wave model of light propagation and for diagrams of plane waves approaching a plane boundary obliquely, and being refracted; 

(d) 
the conditions for total internal reflection; 

(e) 
the derivation and use of the equation for the critical angle: ; 

(f) 
how to apply the concept of total internal reflection to multimode optical fibres; 

(g) 
the problem of multimode dispersion with optical fibres in terms of limiting the rate of data transfer and transmission distance; 

(h) 
how the introduction of monomode optical fibres has allowed for much greater transmission rates and distances. 

7. Photons 

(a) 
The fact that light can be shown to consist of discrete packets (photons) of energy; 
Quantum Physics 1 
(b) 
how the photoelectric effect can be demonstrated; 

(c) 
how a vacuum photocell can be used to measure the maximum kinetic energy, E_{k max}, of emitted electrons in eV and hence in J; 
Quantum Physics 2 
(d) 
the graph of E_{k max} against frequency of illuminating radiation; 

(e) 
how a photon picture of light leads to Einstein's equation:
and how this equation correlates with the graph of E_{k max} against frequency; 

(f) 
the fact that the visible spectrum runs approximately from 700 nm (red end) to 400 nm (violet end) and the orders of magnitude of the wavelengths of the other named regions of the electromagnetic spectrum; 
Particles 3 
(g) 
typical photon energies for these radiations; 

(h) 
how to produce line emission and line absorption spectra from atoms; 
Quantum Physics 3 
(i) 
the appearance of such spectra as seen in a diffraction grating; 
Waves 8 
(j) 
simple atomic energy level diagrams, together with the photon hypothesis, line emission and line absorption spectra; 
Quantum Physics 4 
(k) 
how to determine ionisation energies from an energy level diagram; 

(l) 
the demonstration of electron diffraction and that particles have a wavelike aspect; 
Quantum Physics 6 
(m) 
the use of the relationship:
for both particles of matter and photons; 

(n) 
the calculation of radiation pressure on a surface absorbing or reflecting photons. 
Quantum Physics 7 
8. LASERS 

(a) 
The process of stimulated emission and how this process leads to light emission that is coherent; 
Quantum Physics 8 
(b) 
the idea that a population inversion (N_{2} > N_{1}) is necessary for a laser to operate; 

(c) 
the idea that a population inversion is not (usually) possible with a 2level energy system 

(d) 
how a population inversion is attained in 3 and 4level energy systems; 

(e) 
the process of pumping and its purpose; 

(f) 
the structure of a typical laser i.e. an amplifying medium between two mirrors, one of which partially transmits light; 

(g) 
the advantages and uses of a semiconductor laser i.e. small, cheap, far more efficient than other types of laser, and it is used for CDs, DVDs, telecommunication etc 

And that is it for the AS level 