Unit Overview

Electricity and Magnetism

CIE IGCSE Physics· 5 min read 📊 20-25% of total exam (covers MCQ, structured and extended response questions)

1. Unit at a glance

The unit is structured to build progressively from static foundational phenomena to dynamic applied systems: you will first learn core properties of magnets and static charge, before moving to quantitative circuit principles, and finally exploring the two-way relationship between electricity and magnetism for real-world technologies.

Core quantitative skills including circuit calculations and power computations are reinforced throughout the unit, with extended-only content marked clearly for higher-tier candidates.

Work through the following subtopics in order to build mastery progressively:

Simple Phenomena of Magnetism

Covers permanent magnets, magnetic field patterns, and magnetic induction properties.

★★⏱ 6 min

Electric Charge and Electric Fields

Explores static charge, charging by friction, electric field patterns, and discharge effects.

★★⏱ 7 min

Electric Current, e.m.f. and Potential Difference

Defines current, electromotive force, and potential difference linked to charge and energy transfer.

★★★⏱ 8 min

Resistance

Covers factors affecting resistance, Ohm’s Law, and I-V characteristics for common components.

★★★⏱ 8 min

Electrical Energy, Power and the kW·h

Calculates electrical energy and power, plus use of the kilowatt-hour for domestic energy billing.

★★★⏱ 7 min

Circuit Diagrams, Components and Potential Dividers

Interprets standard circuit symbols, component functions, and potential divider operation.

★★★⏱ 9 min

Series and Parallel Circuits

Applies current, voltage, and resistance rules to solve series and parallel circuit problems.

★★★★⏱ 10 min

Electrical Safety

Covers domestic circuit safety features including fuses, circuit breakers, and earthing systems.

★★⏱ 6 min

Electromagnetic Induction

Explains electromagnetic induction principles and factors affecting induced current size.

★★★★⏱ 8 min

The a.c. Generator (Extended Only)

Covers structure and operation of alternating current generators, for extended tier candidates only.

★★★★⏱ 7 min

Magnetic Effect of a Current, the Motor Effect and the d.c. Motor

Explores magnetic fields around current-carrying conductors, the motor effect, and d.c. motor operation.

★★★★⏱ 9 min

The Transformer

Covers transformer structure, operation, efficiency calculations, and use in power transmission systems.

★★★★⏱ 8 min

2. Common Pitfalls

Wrong move:

Confusing e.m.f. and potential difference as identical quantities

Why:

E.m.f. measures energy supplied to charge per unit, while p.d. measures energy transferred by charge across a component

Correct move:

Use context of energy source vs load to distinguish the two terms in calculations

Wrong move:

Adding resistance values directly for parallel circuits as you do for series circuits

Why:

Total resistance in parallel is less than the smallest individual resistor, calculated via the reciprocal rule

Correct move:

Apply $1/ R_{t o t a l} = 1/ R_{1} + 1/ R_{2} + ...$ for parallel circuits, $R_{t o t a l} = R_{1} + R_{2} + ...$ for series circuits

Wrong move:

Assuming transformers can operate on direct current (d.c.) inputs

Why:

Transformers require changing magnetic fields to induce voltage, which d.c. cannot produce

Correct move:

Only use transformers with alternating current (a.c.) supplies as specified in syllabus questions

3. Quick Reference Cheatsheet

Concept	Formula/Rule	Subtopic Reference
Ohm's Law	$V = I R$	Resistance
Electrical Power	$P = V I = I^{2} R = V^{2} / R$	Electrical Energy, Power and the kW·h
Series Circuit Current	$I_{t o t a l} = I_{1} = I_{2} = ...$	Series and Parallel Circuits
Parallel Circuit Voltage	$V_{t o t a l} = V_{1} = V_{2} = ...$	Series and Parallel Circuits
Transformer Turns Rule	$V_{p} / V_{s} = N_{p} / N_{s}$	The Transformer
Charge Calculation	$Q = I t$	Electric Current, e.m.f. and Potential Difference
Electrical Energy	$E = V I t = P t$	Electrical Energy, Power and the kW·h
Ideal Transformer Power	$V_{p} I_{p} = V_{s} I_{s}$	The Transformer

What's Next

To start your study of this unit, begin with the first subtopic on Simple Phenomena of Magnetism, which introduces the foundational magnetic properties you will build on for all subsequent circuit and electromagnetism content. Once you have completed all subtopics in this unit, you will progress to Unit 5: Atomic Physics, which covers nuclear structure, radioactivity, and related applications aligned with the CIE IGCSE 0625 syllabus.