Physics

4.1.1 Energy changes in a system

• Elastic potential energy of a stretched spring (Ee = 1/2 k e^2)
• Energy stores and systems
• Gravitational potential energy (Ep = m g h)
• Kinetic energy calculation (Ek = 1/2 m v^2)
• Power (P = E/t and P = W/t)
• Required practical 1: specific heat capacity
• Specific heat capacity (ΔE = m c Δθ)

4.1.2 Conservation and dissipation of energy

• Conservation and dissipation of energy
• Efficiency
• Reducing unwanted energy transfers and thermal conductivityHigher
• Required practical 2: thermal insulators (physics only)

4.1.3 National and global energy resources

• National and global energy resources

4.2.1 Current, potential difference and resistance

• Current, resistance and potential difference (V = I R)
• Diodes
• Electrical charge and current (Q = I t)
• Ohmic conductors and resistors with changing resistance
• Required practical 3: factors affecting resistance
• Required practical 4: I–V characteristics
• Standard circuit diagram symbols
• Thermistors and LDRs

4.2.2 Series and parallel circuits

• Series and parallel circuits

4.2.3 Domestic uses and safety

• Direct and alternating potential difference
• Mains electricity wiring (live, neutral, earth)

4.2.4 Energy transfers

• Electrical power (P = V I and P = I^2 R)
• Energy transfers in everyday appliances (E = P t and E = Q V)
• The National Grid

4.2.5 Static electricity (physics only)

• Electric fields (physics only)
• Static electricity and charging by friction (physics only)

4.3.1 Changes of state and the particle model

• Changes of state and conservation of mass
• Density of materials (ρ = m/V)
• Required practical 5: density of solids and liquids

4.3.2 Internal energy and energy transfers

• Internal energy
• Specific latent heat (E = m L)
• Temperature changes and specific heat capacity (revisited)

4.3.3 Particle model and pressure

• Doing work on a gas (physics only, HT only)
• Particle motion in gases
• Pressure in gases (Boyle's law, p V = constant) (physics only)

4.4.1 Atoms and isotopes

• Development of the atomic model (history)
• Mass number, atomic number and isotopes
• The structure of an atom

4.4.2 Atoms and nuclear radiation

• Half-life and the random nature of decay
• Nuclear equations
• Radioactive contamination vs irradiation
• Radioactive decay and nuclear radiation

4.4.3 Hazards and uses of radioactive emissions and of background radiation (physics only)

• Background radiation (physics only)
• Different half-lives of radioactive isotopes (physics only)
• Uses of nuclear radiation (physics only)

4.4.4 Nuclear fission and fusion (physics only)

• Nuclear fission (physics only)
• Nuclear fusion (physics only)

4.5.1 Forces and their interactions

• Contact and non-contact forces
• Gravity, weight and centre of mass (W = m g)
• Resultant forces and resolving forces
• Scalar and vector quantities

4.5.2 Work done and energy transfer

• Work done and energy transfer (W = F s)

4.5.3 Forces and elasticity

• Forces and elasticity (Hooke's law, F = k e)
• Required practical 6: force vs extension for a spring

4.5.4 Moments, levers and gears (physics only)

• Moments, levers and gears (physics only)

4.5.5 Pressure and pressure differences in fluids (physics only)

• Atmospheric pressure (physics only)
• Pressure due to a column of liquid (p = h ρ g) (physics only, HT only)
• Pressure in fluids 1 (p = F/A) (physics only)

4.5.6 Forces and motion

• Acceleration (a = Δv/t)
• Braking force, energy and dangers (factors affecting braking distance 2)
• Distance and displacement
• Distance–time graphs
• Factors affecting braking distance
• Newton's First Law
• Newton's Second Law (F = m a)
• Newton's Third Law
• Reaction time
• Required practical 7: force, mass and acceleration
• Speed (s = v t)
• Stopping distance
• Terminal velocity (physics only)
• Velocity

4.5.7 Momentum (HT only)

• Changes in momentum / impulse (F = mΔv/Δt) (physics only, HT only)
• Conservation of momentum (HT only)
• Momentum (p = m v) (HT only)

4.6.1 Waves in air, fluids and solids

• Properties of waves (amplitude, wavelength, frequency, period; v = f λ)
• Reflection of waves and ray diagrams (physics only)
• Required practical 8: waves in a ripple tank and solid
• Required practical 9: reflection and refraction of light (physics only)
• Sound waves and human hearing (physics only, HT only)
• Transverse and longitudinal waves
• Ultrasound and seismic waves (physics only, HT only)

4.6.2 Electromagnetic waves

• Lenses (convex and concave) and ray diagrams (physics only)
• Properties of electromagnetic waves 1 (refraction at boundary) (HT only)
• Properties of EM waves 2 — generation and dangers (HT only)
• Required practical 10: infrared absorption/emission
• Types of electromagnetic waves (EM spectrum)
• Uses and applications of electromagnetic waves
• Visible light and colour (physics only)

4.6.3 Black body radiation (physics only)

• Black body radiation – emission and absorption (physics only)
• Perfect black bodies and Earth's temperature (physics only)

4.7.1 Permanent and induced magnetism, magnetic forces and fields

• Magnetic fields and the compass
• Poles of a magnet (permanent vs induced)

4.7.2 The motor effect

• Electric motors (HT only)
• Electromagnetism and solenoids
• Fleming's left-hand rule and motor effect (F = B I l) (HT only)
• Loudspeakers and headphones (physics only, HT only)

4.7.3 Induced potential, transformers and the National Grid (physics only) (HT only)

• Alternator and dynamo (physics only, HT only)
• Induced potential / generator effect (physics only, HT only)
• Microphones (physics only, HT only)
• Transformers (physics only, HT only)

4.8.1 Solar system; stability of orbital motions; satellites (physics only)

• Life cycle of a star
• Orbital motion and satellites
• Our solar system

4.8.2 Red-shift (physics only)

• Red-shift and the Big Bang