Why appliances are connected in parallel, the live, neutral and earth wires, how fuses and circuit breakers protect circuits, choosing a suitable rating, and the effects of incorrect or fluctuating voltage.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
A fuse is a deliberate weak link: it is built to fail first so that your wiring, your appliance, and you, do not.
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
Full voltage to each appliance; independent switching; one failure does not stop the rest.
Brown; carries supply voltage; fuse and switch here.
Blue; completes the circuit.
Green/yellow; connects the metal casing to ground.
Thin wire in the live wire that melts if the current is too high.
Trips when the current is too high; can be reset.
I = P/V; choose a rating just above the normal current.
Too high: overheating; too low: poor operation; surges: damage.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness. More games in the Physics Arcade.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better. Work each item on paper first.
Write full answers, then reveal the mark scheme and tick the points you earned (15 marks in total). Show all your working — method marks count. Your answers are saved on this device.
Question 1 [15 marks]
An electric kettle is rated 1 800 W, 120 V. It is connected by a three-core cable to a three-pin plug.
(a) (a) Name the three wires and give the colour of each. [3]
(b) (b) Calculate the normal current drawn by the kettle. [3]
(c) (c) State a suitable rating for the fuse or circuit breaker and give a reason. [2]
(d) (d) Explain how the fuse protects the circuit. [2]
(e) (e) Explain the purpose of the earth wire connected to the metal case. [3]
(f) (f) State two reasons why appliances in a house are connected in parallel. [2]
Find these in your own past-paper booklets for extra timed practice. Items above are written in the style of these papers; any adapted from a specific question say so.