IPhO Electricity & Magnetism
IPhO E&M hub: electrostatics, magnetostatics, and circuit techniques with symmetry and approximation-first thinking.
Before you begin
IPhO E&M problems often look complicated because the geometry is complicated. The winning move is usually to spot symmetry, choose the right surface or loop, or reduce a circuit to one equivalent element.
Be comfortable with: A-Level electric fields, current electricity, D.C. circuits, electromagnetic forces and electromagnetic induction, and the IPhO problem-solving framework.
Learning goals
- Apply electricity & magnetism models and problem-solving methods in competition settings.
Lessons
Work through them in order.
Build the bridge
Build the official core
- Capacitance, Energy & Method of Images (IPhO E&M)Find capacitance from geometry, forces from energy, and fields near grounded conductors by the method of images.
- Circuit Reduction: Thevenin & Norton (IPhO)Reduce a network to its Thévenin or Norton equivalent and check the result with limiting cases.
- Magnetostatics: Ampere & Biot-Savart (IPhO E&M)Choose between Ampère's law and Biot–Savart to find magnetic fields and forces quickly.
Transfer to unfamiliar problems
Practise and check
Recommended nextElectricity & Magnetism topic check
Topic reference
What you should be able to do
- Use symmetry to choose a field method and state why the field has the required direction or constancy.
- Reduce electrostatic and circuit systems using potentials, energy, equivalent sources and time-scale reasoning.
- Apply magnetic-force, Ampere, Biot-Savart and induction ideas with consistent directions, signs and limiting checks.
Official scope: Stages selected electrostatics, circuits and magnetic-field methods from the official electromagnetic-field coverage.
Training habits
- Before touching equations, write down what symmetry you have.
- For circuits, derive the equivalent, then sanity-check limiting cases.