Electrical Energy Efficiency

• Describe how energy in chemical stores, such as batteries or power station fuels, is transferred by an electric current to do work on domestic devices.
• Explain the relationship between the power ratings of domestic electrical appliances, their time of use, and the changes in stored energy.
• Calculate the energy transfers by electrical appliances using the relevant equation.

$E = P \times t$

• Use qualitative examples to describe how, when energy is transferred within a closed system, the system's total energy does not change overall.