Electricity is a core part of A-Level Physics. Revise the key concepts and common mistakes below, then lock them in with the free games.
Key concepts
CurrentRate of flow of charge, measured in amperes.
Potential differenceEnergy transferred per unit charge, measured in volts.
ResistanceOpposition to current; V = IR (Ohm's law).
Series circuitsOne path; current is the same throughout.
Parallel circuitsMultiple paths; pd is the same across each branch.
Electrical powerP = VI; the rate of energy transfer.
Common mistakes to avoid
Questions where students often pick the tempting wrong answer — make sure you know the right one:
What does voltage (potential difference) across a component represent?✗ Voltage is the 'amount of electricity' flowing through the wire. ✓ The energy transferred per unit charge passing through that component.
What happens to the total resistance when you add another resistor in parallel?✗ Adding any resistor always increases the total resistance. ✓ Total resistance decreases — there are more paths for current to flow.
In a series circuit with two identical bulbs:✗ each bulb gets full supply voltage ✓ voltage is shared equally
For a projectile launched horizontally, what affects the horizontal component of velocity during flight (ignoring air resistance)?✗ Gravity slows down both the vertical and horizontal motion. ✓ Nothing — horizontal velocity stays constant; only vertical velocity changes due to gravity.
In which direction does an electric field point near a positive charge?✗ Radially inwards because positive attracts negative. ✓ Radially outwards — the field is defined by the force on a positive test charge, which is repelled.
Practise Electricity — free games
Test yourself with these quick revision games for this topic:
See all 17 games in the Subjects Arcade →
More A-Level Physics topics
← All revision guides
Want to revise every topic this smart?
The Velvet Method teaches you to use AI to revise any subject — £25, lifetime access.
Explore the Course →