The modules, one by one
Each area below lists the concepts named in the course document, what the TASC exam asks of them, and the mistake that most often costs marks.
- Kinematics and motion graphs
- Projectile motion
- Momentum, impulse, work and energy
- Newton's laws and circular motion
- Gravitation and orbits
- Electrostatics and point-charge fields
- Uniform fields and accelerated charges
- Magnetic fields and forces on currents
- Charged particles in magnetic fields
- Electromagnetic induction
- Wave properties and pulses at boundaries
- Refraction and total internal reflection
- Superposition, beats and standing waves
- Two-source interference
- Diffraction and polarisation
- Black bodies and the photoelectric effect
- X-rays, photon momentum and matter waves
- Energy levels and spectra
- Radioactive decay and half-life
- Mass defect, binding energy and nuclear energy
Area 1 of 20
Kinematics and motion graphs
Treat displacement, velocity and acceleration as vectors. Slopes of s–t and v–t graphs give velocity and acceleration; the area under a v–t graph gives displacement. Use the constant-acceleration equations with one sign convention throughout, including vertical motion with g = 9.81 m s⁻².
What the exam asks
External Criterion 5 (Section A): identify and apply principles of Newtonian mechanics including gravitational fields.
Where marks go missing
Drawing curved lines on a constant-acceleration v–t graph, or giving an upward and downward trip the same acceleration when friction acts.
Area 2 of 20
Projectile motion
Split the launch velocity into components, keep horizontal velocity constant and apply uniform acceleration vertically. Launch and landing heights can differ, so solve the vertical equation for time first, then use it horizontally.
What the exam asks
External Criterion 5 (Section A): identify and apply principles of Newtonian mechanics including gravitational fields.
Where marks go missing
Treating the path as a straight hypotenuse, or forgetting the launch speed is not zero when an object leaves a ramp.
Area 3 of 20
Momentum, impulse, work and energy
Impulse FΔt equals the change in momentum, and momentum is conserved in collisions and explosions in two dimensions. Use vector triangles with the cosine and sine rules. Compare kinetic energy before and after to classify a collision, and use W = Fs cos θ and P = W/t.
What the exam asks
External Criterion 5 (Section A): identify and apply principles of Newtonian mechanics including gravitational fields.
Where marks go missing
Adding momenta as numbers instead of vectors, or assuming a vector triangle is right-angled when it is not.
Area 4 of 20
Newton's laws and circular motion
Draw free-body diagrams with every real force and no 'centripetal force' arrow. Apply ΣF = ma on inclines, to rockets and to mass-flow systems where force equals momentum change per second. In horizontal circles the net force points to the centre: F = mv²/r = 4π²mr/T².
What the exam asks
External Criterion 5 (Section A): identify and apply principles of Newtonian mechanics including gravitational fields.
Where marks go missing
Leaving out weight when finding rocket thrust, or adding friction and gravity components with the wrong signs on an incline.
Area 5 of 20
Gravitation and orbits
F = Gm₁m₂/r² and g = GM/r² use centre-to-centre distance. Add the fields of two masses as vectors, locate the null point, and sketch field lines. Kepler's third law T² = 4π²r³/GM links period and orbital radius for satellites, including geostationary orbits.
What the exam asks
External Criterion 5 (Section A): identify and apply principles of Newtonian mechanics including gravitational fields.
Where marks go missing
Using altitude instead of orbital radius, or using the planet's radius when the orbital radius is needed.
Area 6 of 20
Electrostatics and point-charge fields
Coulomb's law F = kq₁q₂/r² and E = kq/r² give magnitudes; directions come from the sign of the source charge. Combine fields from two charges with a labelled vector diagram, and sketch field lines that start on positive and end on negative charge.
What the exam asks
External Criterion 6 (Section B): identify and apply principles of electricity and magnetism.
Where marks go missing
Forgetting to square r, using one electron charge for a doubly charged ion, or treating a 120° vector problem as a right angle.
Area 7 of 20
Uniform fields and accelerated charges
Between parallel plates E = V/d and a charge gains qV of kinetic energy. A charge entering perpendicular to the field follows a parabola like a projectile. Millikan's oil-drop method balances qE against mg.
What the exam asks
External Criterion 6 (Section B): identify and apply principles of electricity and magnetism.
Where marks go missing
Confusing the field symbol E with energy, or explaining acceleration only as 'attraction' without naming the field and net force.
Area 8 of 20
Magnetic fields and forces on currents
A long straight wire produces B = kI/r in circles given by a right-hand rule. A current in a field feels F = IlB sin θ; parallel currents attract and antiparallel currents repel with F/l = kI₁I₂/r. Motors use this force with a split-ring commutator.
What the exam asks
External Criterion 6 (Section B): identify and apply principles of electricity and magnetism.
Where marks go missing
Calculating a force on an assumed 1 m instead of a force per unit length, or forgetting to multiply by the number of turns in a coil.
Area 9 of 20
Charged particles in magnetic fields
A moving charge feels F = qvB sin θ at right angles to its velocity, so it moves in a circle of radius r = mv/qB, or a helix if it has a component along B. Crossed fields pass only v = E/B, and the Bainbridge spectrometer separates isotopes by radius.
What the exam asks
External Criterion 6 (Section B): identify and apply principles of electricity and magnetism.
Where marks go missing
Giving a force component along the field direction, or forgetting that an electron's force is opposite to a positive charge's.
Area 10 of 20
Electromagnetic induction
A conductor moving through a field has emf = vlB sin θ, and a closed circuit carries I = V/R. Lenz's law makes the induced current oppose the change, so work done against the opposing force becomes electrical energy and then heat. Generators, eddy currents and transformers apply the same idea.
What the exam asks
External Criterion 6 (Section B): identify and apply principles of electricity and magnetism.
Where marks go missing
Confusing emf with the force on the rod, or describing energy transfer in only one step.
Area 11 of 20
Wave properties and pulses at boundaries
Waves carry energy without carrying matter. v = fλ and f = 1/T link the graphs. A pulse inverts on reflection from a fixed end and stays upright at a free end; on a string v = √(T/μ), so a heavier string carries a slower, shorter-wavelength transmitted pulse.
What the exam asks
External Criterion 7 (Section C): identify and apply general principles of wave motion.
Where marks go missing
Using a mass instead of a tension in v = √(T/μ), or leaving linear density in g m⁻¹.
Area 12 of 20
Refraction and total internal reflection
Snell's law n₁ sin θ₁ = n₂ sin θ₂ uses angles from the normal. Different colours have different refractive indices, so a prism disperses white light. Total internal reflection needs light travelling from a slower to a faster medium at more than the critical angle.
What the exam asks
External Criterion 7 (Section C): identify and apply general principles of wave motion.
Where marks go missing
Bending the ray away from the normal on entering glass, or claiming no reflection at all when the critical angle is not reached.
Area 13 of 20
Superposition, beats and standing waves
Overlapping waves add. Two close frequencies give beats at |f₁ − f₂|. Standing waves form from reflected waves: strings and open pipes have f = nv/2L, closed pipes have only odd harmonics f = nv/4L. Resonance builds energy at a natural frequency.
What the exam asks
External Criterion 7 (Section C): identify and apply general principles of wave motion.
Where marks go missing
Confusing the second overtone with the second harmonic, or putting a node at an open end.
Area 14 of 20
Two-source interference
Coherent sources produce maxima where the path difference is a whole number of wavelengths and minima at half-wavelengths. For a distant screen the fringe (band) width is w = λx/d. The same method works for light, sound, radio and water waves.
What the exam asks
External Criterion 7 (Section C): identify and apply general principles of wave motion.
Where marks go missing
Calculating path difference with trigonometry instead of subtracting the two distances.
Area 15 of 20
Diffraction and polarisation
Diffraction is greatest when the gap or obstacle is comparable to the wavelength, which limits resolution and helps long-wavelength signals bend round obstacles. Only transverse waves polarise; reflection, transmission and scattering partly polarise light.
What the exam asks
External Criterion 7 (Section C): identify and apply general principles of wave motion.
Where marks go missing
Saying sound can be polarised, or that a polarising filter blocks all reflected light at every angle.
Area 16 of 20
Black bodies and the photoelectric effect
Planck explained black-body spectra with quantised energy; Wien's law gives λ_max T = 2.90 × 10⁻³ m K. Einstein's equation Ek(max) = hf − W = eV₀ means a graph of stopping voltage against frequency has gradient h/e (h in eV s) and intercepts that give the threshold frequency and work function.
What the exam asks
External Criterion 8 (Section D): wave-particle nature of light, atomic and nuclear physics.
Where marks go missing
Thinking brighter light raises the maximum kinetic energy, or reading the gradient without converting units.
Area 17 of 20
X-rays, photon momentum and matter waves
X-ray tubes give a continuous spectrum with f_max = eV/h plus characteristic lines. Photons carry momentum p = h/λ, so Compton scattering conserves vector momentum. de Broglie's λ = h/p gives particles wave behaviour, strongest at low momentum.
What the exam asks
External Criterion 8 (Section D): wave-particle nature of light, atomic and nuclear physics.
Where marks go missing
Treating a back-scattered photon's momentum as positive, or using h in eV s with momentum in kg m s⁻¹.
Area 18 of 20
Energy levels and spectra
Electrons occupy discrete levels. Moving between them absorbs or emits a photon with ΔE = hf = hc/λ. Electron collisions can excite an atom if they carry at least the level gap, and the scattered electron keeps the rest; photons must match a gap exactly unless they ionise.
What the exam asks
External Criterion 8 (Section D): wave-particle nature of light, atomic and nuclear physics.
Where marks go missing
Assuming excitation happens in upward steps, or dropping the scattered electron's leftover energy.
Area 19 of 20
Radioactive decay and half-life
Alpha, beta-minus (with antineutrino), beta-plus (with neutrino) and gamma emissions conserve charge and nucleon number. Activity A = λN, λ = 0.693/T½ and N = N₀e^(−λt); convert between mass and number of atoms with N = mN_A/M.
What the exam asks
External Criterion 8 (Section D): wave-particle nature of light, atomic and nuclear physics.
Where marks go missing
Mixing time units between λ and t, or omitting the antineutrino from a beta-minus equation.
Area 20 of 20
Mass defect, binding energy and nuclear energy
Mass defect × 931 MeV per u gives binding energy; the binding energy per nucleon curve peaks near iron, so fusion of light nuclei and fission of heavy nuclei release energy. Reactors need moderators, control rods and heat exchangers. The strong force is short-range; nucleons are up/down quarks held by gluons.
What the exam asks
External Criterion 8 (Section D): wave-particle nature of light, atomic and nuclear physics.
Where marks go missing
Forgetting the electron masses when using atomic masses, or giving total binding energy when binding energy per nucleon is asked for.