Cambridge IGCSE·Co-ordinated Sciences 0654·Physics
Electricity Magnetism
Key knowledge — Electricity Magnetism
Formulas & equations
Ohm's law: V = IR (voltage = current × resistance)Power: P = IV = I²R = V²/REnergy: E = IVt = PtSeries circuit: R_total = R₁ + R₂ + …Parallel circuit: 1/R_total = 1/R₁ + 1/R₂ + …Charge: Q = It (coulombs = amperes × seconds)Transformer: V₁/V₂ = N₁/N₂ (ideal: V₁I₁ = V₂I₂)
Key facts & rules
- Current: flow of charge (electrons in metals). Unit: ampere (A). Measured with ammeter (in series).
- Voltage (pd): energy transferred per unit charge. Unit: volt (V). Measured with voltmeter (in parallel).
- Resistance: opposition to current. Unit: ohm (Ω).
- Series circuit: same current everywhere; voltage splits; resistance adds.
- Parallel circuit: same voltage across each branch; current splits; total resistance less than smallest.
- Direct current (DC): current always in same direction (batteries).
- Alternating current (AC): current reverses direction periodically (mains electricity, 50 Hz in UK).
- Magnetic field: caused by moving charges/current. Right-hand rule for solenoid.
- Motor effect: current-carrying conductor in magnetic field experiences a force (F = BIl).
- Electromagnetic induction: moving conductor in magnetic field (or changing flux) induces EMF.
- Step-up transformer: more turns on secondary → higher voltage, lower current.
- Step-down transformer: fewer turns on secondary → lower voltage, higher current.
IGCSE Physics — Electricity & magnetism
5181 Cambridge IGCSE 0654 physics past paper questions on electricity & magnetism, organised by subtopic. Pick a subtopic to start practising.
About electricity & magnetism on IGCSE 0654
Static electricity, current, voltage and resistance, circuits, electrical energy, magnetism and electromagnetism.