Reducing Heating in Circuits (Edexcel GCSE Physics): Revision Note

Explaining Heating in Circuits

• When electricity passes through a component, there is energy transferred to heat

• This is due to collisions between:

  • Electrons flowing in the conductor, and

  • The lattice of atoms within the metal conductor

• Electricity, in metals, is caused by a flow of electrons

  • This is called the current

• Metals are made up of a lattice of ions

• As the electrons pass through the metal lattice they collide with ions

  • The ions resist the flow of the electrons

As electrons flow through the metal, they collide with ions, making them vibrate more

• When the electrons collide, they lose some energy by giving it to the ions, which start to vibrate more

  • As a result of this, the metal heats up

• This heating effect is utilised in many appliances, including:

  • Electric heaters

  • Electric ovens

  • Electric hob

  • Toasters

  • Kettles

Reducing Heating in Circuits

• In most electrical appliances, the heat is not wanted

  • As well as being unwanted, it can also be dangerous

• The amount of heat created in wires can be reduced in a couple of ways:

  • Reduce the current in the wires

  • Uses wires with a lower resistance

• Copper is usually used in electrical wiring as it has a relatively low resistance and is fairly cheap

  • Lower resistance alternatives exist, but they are more expensive