b) electromotive force

• state what potential difference describes in terms of work done

• when work is done by charge carriers on a component

• so the charge carriers are losing energy

• state what electromotive force describes in terms of work done

• when work is done on charge carriers by a component (cell, battery, or power supply)

• so the charge carriers are gaining energy

• state the relationship between potential difference and electromotive force

• potential difference = electromotive force (usually)

• VQ = εQ

• define electromotive force

• the joules of chemical energy transferred from a component to the electrical store of one coulomb of charge

• 1V = ?

• 2V = ?

• 1J of chemical energy transferred from the component to 1C of charge

• 2J of chemical energy transferred from the component to 1C of charge

• state the formula for electromotive force

• ε = W / Q

• electromotive force (V) = chemical energy transferred (J) / charge (C)