Worked example
Use Ohm’s law
A 4 Ω resistor is connected across 12 V. Find the current.
- Use V = IR.
- Rearrange to I = V ÷ R.
- I = 12 ÷ 4 = 3.
Answer The current is 3 A.
Physics / Science
Electricity
Connect circuits, current, voltage, resistance and magnetism.
Understand the concept
Electric current is the rate at which charge flows through a complete circuit. Potential difference supplies energy per unit charge, while resistance opposes current.
Current also creates a magnetic field. This connection makes electromagnets, motors and many electrical devices possible.