Introduction
 

The principle of conservation of energy is fundamental to Physics and underpins all electrical calculations. In electrical circuits, energy supplied by a source is transferred to components where it may be converted into useful forms such as light or kinetic energy, or dissipated as thermal energy. Understanding how energy is conserved allows students to analyse electrical circuits and solve a wide range of examination problems.
 

In this topic, students learn to apply the conservation of energy to electrical circuits, select appropriate equations, and carry out calculations involving current, potential difference, resistance, power and energy.
 

AQA A Level Physics Specification: 3.2.4 Electricity
 

What You Need to Know
 

• Apply the principle of conservation of energy to electrical circuits.

• Understand that the total energy supplied by a source equals the total energy transferred to circuit components.

• Calculate electrical energy transferred using:

  • E = Pt

  • E = VIt

• Calculate electrical power using:

  • P = VI

  • P = I²R

  • P = V²/R

• Select and apply the appropriate electrical equation when solving multi-step calculations.

• Calculate the energy dissipated in resistors and other circuit components.

• Use conservation of energy to analyse circuits containing cells with internal resistance.

• Solve examination questions involving combinations of current, potential difference, resistance, power and energy.
   

Downloadable Topic Pack
 

The Conservation of Energy and Electricity Calculations Topic Pack Exam Questions and Answers
 

Related Topics
 

• Energy & Power

• EMF and Internal Resistance

• The Potential Divider

• IV Characteristics and Electricity Basics

• Resistivity & Superconductors