Voltage

Types of voltage

There are two types of energy transfers in

When energy is ‘lost’ by a coulomb (i.e. ‘given’ to a component), it’s called ‘potential difference’.
When energy is ‘gained’ by a coulomb (usually from a cell), it’s called ‘EMF’.

Potential difference is the work done by unit charge.
It’s a type of voltage that represents the energy transferred to or from a component in a circuit (not from the cell/battery).
If the potential difference across a component is, for example, 6V, that menas that 1C of charge transfers 6J of energy to the component.
It’s called the ‘potential difference’ because it is the difference in energy (work done) or volts across a component.
Potential difference can be measured with a voltmeter.

\text{potential difference} = \frac{\text{work done}}{\text{charge}}

V=\frac WQ

\text{potential difference} = \text{current} \times \text{resistance}

V=IR

Question	Answer
What are the two types of voltage based on how energy is transferred by a coulomb?	- Potential difference: when energy is ‘lost’ (given to a component). - EMF: when energy is ‘gained’ (usually from a cell).
What is potential difference?	The work done by unit charge.
What does a 6V potential difference across a component mean?	1C of charge transfers 6J of energy to the component.
What instrument is used to measure potential difference?	A voltmeter.
What is the equation relating potential difference, work done, and charge?	V = \frac{W}{Q}
What is the equation relating potential difference, current, and resistance?	V = IR