  Welsh Board A2 Syllabus - Options Home       AS       A2   Options There are FOUR options of which you chose ONE.  Actually your tutor will choose it unless you are lucky enough to study in a college that has four or more Physics A2 groups. In the exam, you are expected to demonstrate and apply knowledge of: Option A Alternating Currents A more detailed account of AC Theory can be found HERE (a) Using Faraday's law, the principle of electromagnetic induction applied to a rotating coil in a magnetic field (b) the idea that the flux linkage of a rotating flat coil in a uniform magnetic B-field is BAN cos ωt because the angle between the coil normal and the field can be expressed as θ =ωt; (c) the equation V = BANω sin ωt for the induced emf in a rotating flat coil in a uniform B-field; (d) the terms frequency, period, peak value and rms value when applied to alternating potential differences and currents; (e) the idea that the rms value is related to the energy dissipated per cycle, and use the relationships: (f) the idea that the mean power dissipated in a resistor is given by: where V and I are the rms values; (g) the use of an oscilloscope (CRO or PC based via USB or sound card) to measure: • a.c. and d.c. voltages and currents • frequencies; (h) the 90° phase lag of current behind potential difference for an inductor in a sinusoidal a.c. circuit; (i) the idea that: is called the reactance, XL , of the inductor, and to use the equation XL = ωL; (j) the 90° phase lead of current ahead of potential difference for a capacitor in a sinusoidal a.c. circuit, and to use the equation: (k) the idea that the mean power dissipation in an inductor or a capacitor is zero; (l) how to add potential differences across series RC, RL, and RCL combinations using phasors; (m) how to calculate phase angle and impedance, Z, (defined as: for such circuits); (n) how to derive an expression for the resonance frequency of an RCL series circuit; (o) the idea that the Q factor of a RCL circuit is the ratio: at resonance. (p) the idea that the sharpness of the resonance curve is determined by the Q factor of the circuit. Option B Medical Physics (a) The nature and properties of X-rays; (b) the production of X-ray spectra including methods of controlling the beam intensity and photon energy; (c) the use of high energy X-rays in the treatment of patients (therapy) and low energy X-rays in diagnosis; (d) the equation: for the attenuation of X-rays; (e) the use of X-rays in imaging soft tissue, and fluoroscopy to produce real time X-rays using image intensifiers; (f) techniques of radiography including using digital image receptors; (g) the use of a rotating beam X-ray computed tomography (CT) scanner; (h) the generation and detection of ultrasound using piezoelectric transducers; (i) scanning with ultrasound for diagnosis including A-scans and B-scans incorporating examples and applications; (j) the significance of acoustic impedance, defined by Z = c ρ for the reflection and transmission of sound waves at tissue boundaries, including the need for a coupling medium; (k) the use of the Doppler Equation: to study blood flow using an ultrasound probe; (l) the principles of magnetic resonance with reference to precession nuclei, resonance and relaxation time, and to apply the equation f = 42.6 × 106 B  for the Larmor frequency; (m) the use of MRI in obtaining diagnostic information about internal structures; (n) the advantages and disadvantages of ultrasound imaging, X-ray imaging and MRI in examining internal structures; (o) the effects of α, β, and γ radiation on living matter;   the Gray (Gy) as the unit of absorbed dose and the Sievert (Sv) as the unit of equivalent dose and effective dose. Define absorbed dose as energy per kilogram; (p) the use of the equations  equivalent dose = absorbed dose × (radiation) weighting factor  H = DWR  effective dose = equivalent dose × tissue weighting factor  E = HWT; (q) the uses of radionuclides as tracers to image body parts with particular reference to technetium-99m (Tc-99m); (r) the use of the gamma camera including the principles of the collimator, scintillation counter and photomultiplier / CCD; (s) positron emission tomography (PET) scanning and its use in detecting tumours. Option C The Physics of Sports (a) How to use the centre of gravity to explain how stability and toppling is achieved in various sporting contexts; Mechanics 4 (b) How to use the principle of moments to determine forces within:  various muscle systems in the human body and  other sporting contexts, for example, sailing; (c) how to use Newton’s 2nd law in the form Ft = mv - mu in various sporting contexts; (d) the coefficient of restitution as: and also use it in the form: where h is the bounce height and H is the drop height; Physics 6 Tutorial 9 (e) what is meant by the moment of inertia of a body; (f) how to use equations to determine the moment of inertia, I, for example:  a solid sphere  a thin spherical shell where m is the mass and r is the radius; (g) the idea that angular acceleration, α, is defined as the rate of change of angular velocity, ω, and how to use the equation: ; (h) the idea that torque, τ, is given as τ = Iα; (i) angular momentum, J, is given as J = Iω where ω is the angular velocity; (In the notes, the Physics code L is used instead of J.) (j) the principle of conservation of angular momentum and use it to solve problems in sporting contexts; (k) how to use the equation for the rotational kinetic energy: ; (l) how to use the principle of conservation of energy including the use of linear and rotational kinetic energy as well as gravitational and elastic potential energy in various sporting contexts; (m) how to use projectile motion theory in sporting contexts; (n) how to use Bernoulli’s equation: in sporting contexts; (o) how to determine the magnitude of the drag force using: where CD is the drag coefficient. Option D Energy and the Environment (a) How the following affect the rate at which the temperature of the Earth rises including: (i) the need for thermal equilibrium: that is the balance between energy inflow from the Sun and energy re-radiated from the Earth in the context of global energy demand and the effect of CO2 levels in the atmosphere; (ii) the origin and means of transmission of solar energy and the form of the Sun’s power spectrum including the idea that wavelengths are converted into the near infrared in the atmosphere; (iii) the use of Wien’s law (λmax T = constant) and Stefan-Boltzman T4 law in the context of solar power; (iv) use of the density equation and Archimedes’ principle to explain why rising sea levels are due to melting ice caps and that the melting of ice on land increases sea levels but melting icebergs do not; (b) the common sources of renewable and non-renewable energy and be able to compare their development and use both in the UK and internationally (i) solar power:  the idea that the main branch of the proton-proton chain is the main energy production mechanism in the Sun  the intensity of power from the Sun  and the inverse square law for a point source  how to perform energy conversions using photovoltaic cells (including efficiency calculations)   (ii) wind power:  the power available from a flowing fluid  the factors affecting the efficiency of wind turbines   (iii) tidal barrages, hydroelectric power and pumped storage:  the principles of energy conversion (Ep to Ek) in tidal barrage, hydroelectric and pumped storage schemes and be able to carry out energy and power calculations related to these schemes and compare with the energy produced from wind (iv) nuclear fission and fusion:  the principles underlying breeding and enrichment in nuclear fission applications  the difficulties in producing sustained fusion power - fusion triple product; (c) the principles of fuel cell operation and the benefits of fuel cells particularly regarding greenhouse gas emissions; (d) the thermal conduction equation in the  form: Physics 6 Tutorial 14 (e) the effect of insulation on thermal energy loss and be able to calculate the heat loss for parallel surfaces using the rate of energy transfer =UAΔθ including cases where different materials are in contact. And that is it.