Module 4: Electricity and Magnetism

NSW HSC Physics Year 11

Module Overview

This module introduces electrostatics, electric circuits, and magnetism, providing the foundation for the more advanced electromagnetism concepts in Year 12.

Indicative Hours: 30 hours

Related Outcomes:

  • PH11-11 explains and quantitatively analyses electric fields, circuitry and magnetism

Inquiry Questions

  1. How do charged particles interact with each other and electric fields?

  2. How do magnetised and magnetic objects interact?

Key Concepts

4.1 Electrostatics

Learning Focus

Understand electric charge, electric fields, and Coulomb’s Law.

Content:

  • Describe electric charge and charging by friction, contact, and induction
  • Apply Coulomb’s Law to calculate forces between charges
  • Define electric field strength and calculate fields due to point charges
  • Analyse the motion of charged particles in uniform electric fields

Key Formulas:

Quantity Formula
Coulomb’s Law \(F = k\frac{q_1 q_2}{r^2}\)
Electric field strength \(E = \frac{F}{q} = k\frac{Q}{r^2}\)
Electric potential energy \(U = k\frac{q_1 q_2}{r}\)
Work in electric field \(W = qEd = qV\)

4.2 Electric Circuits

Learning Focus

Analyse DC circuits using Ohm’s Law and Kirchhoff’s Laws.

Content:

  • Define current, voltage, resistance, and power
  • Apply Ohm’s Law to circuit analysis
  • Calculate equivalent resistance in series and parallel circuits
  • Use Kirchhoff’s Laws to analyse complex circuits

Key Formulas:

Quantity Formula
Current \(I = \frac{Q}{t}\)
Ohm’s Law \(V = IR\)
Power \(P = VI = I^2R = \frac{V^2}{R}\)
Series resistance \(R_T = R_1 + R_2 + ...\)
Parallel resistance \(\frac{1}{R_T} = \frac{1}{R_1} + \frac{1}{R_2} + ...\)

4.3 Magnetism

Learning Focus

Understand magnetic fields and their interactions with currents.

Content:

  • Describe magnetic field patterns around permanent magnets and current-carrying conductors
  • Apply the right-hand grip rule to determine field direction
  • Explain magnetic effects of current in solenoids
  • Introduce the concept of magnetic flux

Key Concepts:

  • Magnetic field lines: from north to south pole
  • Current creates a magnetic field (Oersted’s discovery)
  • Solenoid field pattern resembles a bar magnet

Key Definitions

Electric Charge
A fundamental property of matter; measured in coulombs (C).
Electric Field
A region where a charged particle experiences a force.
Electric Field Strength
Force per unit charge at a point in an electric field; measured in N/C or V/m.
Current
The rate of flow of electric charge; measured in amperes (A).
Voltage (Potential Difference)
Energy per unit charge; measured in volts (V).
Resistance
Opposition to current flow; measured in ohms (Ω).
Magnetic Field
A region where a magnetic object experiences a force.
Magnetic Flux
A measure of the total magnetic field passing through a surface; measured in webers (Wb).