# 4.2.4.2

4.2.4.2 Energy transfers in everyday appliances

# 4.2.4.2 Energy transfers in everyday appliances

## Content

• Everyday electrical appliances are designed to bring about energy transfers.

The amount of energy an appliance transfers depends on how long the appliance is switched on for and the power of the appliance.

Students should be able to describe how different domestic appliances transfer energy from batteries or ac mains to the kinetic energy of electric motors or the energy of heating devices.

GCSE Physics (8463). For exams 2018 onwards. Version 1.0

Content

Key opportunities for skills development

Work is done when charge flows in a circuit.

The amount of energy transferred by electrical work can be calculated using the equation:

energy transferred = power × time

E =Pt

energy transferred = charge flow × potential difference

E =QV

energy transferred, E, in joules, J

power, P, in watts, W

time, t, in seconds, s

charge flow, Q, in coulombs, C

potential difference, V, in volts, V

Students should be able to explain how the power of a circuit device is

related to:

• the potential difference across it and the current through it
• the energy transferred over a given time.
• Students should be able to describe, with examples, the relationship between the power ratings for domestic electrical appliances and the changes in stored energy when they are in use.

WS 1.2 Use a variety of models such as representational, spatial, descriptive, computational and mathematical to solve problems, make predictions and to develop scientific explanations and understanding of familiar and unfamiliar facts.

WS 1.4 Explain everyday and technological applications of science; evaluate associated personal, social, economic and environmental implications; and make decisions based on the evaluation of evidence and arguments.

MS 3b Change the subject of an equation

MS 3c Substitute numerical values into algebraic equations using appropriate units for physical quantities