Chapter 4

Electricity and Magnetism

Current, voltage, resistance (V = IR), power, circuits and magnets — with an interactive exercise.

Electricity and Magnetism covers current, voltage, resistance, circuits and magnets.

Key formulae

$V = IR$ (Ohm's Law) · Power $P = VI$

Current is measured in amperes (A), voltage in volts (V), resistance in ohms (Ω). Like magnetic poles repel; unlike poles attract.

Remember

  • $V = IR$ · $P = VI$.
  • Like poles repel; unlike poles attract.

Stuck on this topic? A verified JomKelas tutor can walk you through it.

Find a verified tutor