Potential difference
The Moving electric charges, eg electrons moving through a metal wire. flowing through a component depends on:
- the The opposition in an electrical component to the movement of electrical charge through it. Resistance is measured in ohms. of the Parts of an electrical circuit, eg resistors, lamps, motors etc.
- the The potential difference (or voltage) of a supply is a measure of the energy given to the charge carriers in a circuit. Units = volts (V). This is the voltage between two points that makes an electric current flow between them. across the component
Measuring potential difference
Potential difference is also known as The potential difference across a cell, electrical supply or electrical component. It is measured in volts (V). and is measured in volts (V). The potential difference across a component is measured using a A device used to measure potential difference or voltage. placed In a parallel circuit, the current divides into two or more paths before recombining to complete the circuit. Lamps and other components in these different paths are said to be in parallel. with a component such as a lamp, as shown in this diagram:
Energy, potential difference and charge
When a charge moves through a potential difference, electrical Energy transferred by a force. Work done = force 脳 distance moved in the direction of the force. is done and energy transferred. The energy transferred can be calculated using the equation:
energy transferred = charge 脳 potential difference
This is when:
- energy is measured in joules (J)
- charge is measured in coulombs (C)
- potential difference is measured in volts (V)
Example
2 C of charge transfers 4 J of energy. Calculate the potential difference needed.
Rearrange the equation:
energy transferred = charge 脳 potential difference
potential difference = energy transferred 梅 charge
potential difference = 4 梅 2
= 2 V
Question
3 C of charge moves through a potential difference of 6 V. Calculate the energy transferred.
energy transferred = charge 脳 potential difference
= 3 脳 6
= 18 J