Primary 6 · Science · Systems: Electrical Circuits
Systems: Electrical Circuits questions for Primary 6 Science
10 questions to work through online, 2 of them written out the way the paper asks. Answer and you get the working straight away, then a score at the end. No sign-up, and you can retake it as often as you like.
- Tracing a break
- Comparing brightness
- Why parallel is used
- Finding a fault
- Conductors in a circuit
- Reasoning about brightness
- Reasoning about a switch position
- Naming the arrangement
- Naming a material
- Applying the ideas
| Circuit | Batteries | Bulbs | Arrangement | Brightness of each bulb |
|---|---|---|---|---|
| J | 1 | 1 | single | normal |
| K | 1 | 2 | series | dim |
| L | 1 | 2 | parallel | normal |
| M | 2 | 2 | series | normal |
Answers and explanations for all 10 questions
Every answer with the reasoning behind it. Worth reading after you have tried the set — or on its own, if you are a parent marking it.
In the circuit above, what happens when switch S is opened?
Answer: Bulb A goes out and bulb B stays lit.
Switch S is on the outer loop, which is the path through bulb A. Opening it breaks that path only; bulb B's branch still runs straight to the battery.
Based on the table above, which statement is correct?
Answer: Bulbs in series share the supply, and adding a second battery restores their brightness.
In series, one battery is shared between two bulbs and both are dim. Two batteries restore the share, and in parallel each bulb has its own full path.
Which two reasons explain why household lights are wired in parallel?
Answer: A and B only
Each lamp on its own branch can be switched independently and keeps working when another fails. The extra wiring is the price of both.
In the circuit above, neither bulb lights. Which single fault could explain it?
Answer: Bulb X has blown.
In series there is one path. A single blown bulb breaks it, so neither bulb lights — which is why one fault is enough to explain both being dark.
A gap in a working circuit is bridged with different objects. Which one would light the bulb?
Answer: a steel paper clip
Only a conductor completes the circuit. Steel is a metal and conducts; plastic, dry wood and rubber are all insulators.
A third bulb is added in series to a circuit that already has two bulbs and one battery. Which two things happen?
Answer: A and B only
One battery is now shared three ways, so every bulb is dimmer. And with a single path, removing any bulb breaks it for all of them.
Where must a switch be placed so that it turns off every lamp in a house at once?
Answer: on the main supply, before the wiring branches to the lamps
A switch breaks the path it sits on. Placed before the branches, that path carries every lamp's supply, so opening it puts them all out.
Two bulbs are joined one after another so that the same electricity passes through both, and one failing puts out the other. What is this arrangement called?
Answer: series
Bulbs joined one after another on a single path are in series.
Copper is used for the wire inside a cable because electricity passes through it easily. A material like this is called a ______ .
Answer: conductor
A material electricity passes through easily is a conductor.
A car's headlights stay on when one bulb blows, but its old string of fairy lights all went dark together. What does this tell you?
Answer: The headlights are wired in parallel and the fairy lights were wired in series.
Independent failure means separate paths, which is parallel. Everything failing together means one shared path, which is series.