Electrical Work
Applied Science: BTEC Level 3 National Extended Diploma, topic 3.7.4
Electrical Work
In an electrical circuit, the energy source (battery or power supply) makes a current flow.
Charge flow
- Charge flows from the energy source and through the rest of the circuit and its components, like lamps and heaters.
- The flow of current transfers energy from the energy source to the components.
Energy transfer
- The components then transfer energy to their surroundings.
- For example, a lamp emits light into its surroundings.
Power
Power (P) is the rate of energy transfer to a component.
Power
- The power of a component is equal to the current through the component multiplied by the potential difference across the component.
- P = I x V.
- We know V = IR, so power can also be calculated by:
- P = I2R
Total energy transfer
- The total energy transferred to a component is equal to the power multiplied by the time a current flows for.
- E = P x t.
Test yourself on Electrical Work
Select the relevant units for the equation: power = current x potential difference.
Flow of Energy in an Electric Circuit
When a current flows through a light bulb, it emits 30 J light energy in 2 seconds, what is the power of the bulb?