CIE iGCSE Co-Ordinated Science P4.4 Electrical safety Exam Style Questions Paper 1
Question
A student connects the circuit shown.
When the switch is closed, the fuse blows and stops the current.
What is a possible reason for this?
A. The current rating of the fuse is too high.
B. The current is too large.
C. The lamp is too dim.
D. The voltage is too small.
▶️Answer/Explanation
Answer: B
Explanation: If the current in the circuit exceeds the fuse’s rating, the fuse will blow to protect the circuit. This indicates that the current is too large.
Question
A hairdryer is protected by a 10 A fuse. What is the purpose of the fuse?
A. It decreases the current in the hairdryer to 10 A when the current is more than 10 A.
B. It increases the current in the hairdryer to 10 A when the current is less than 10 A.
C. It maintains a constant temperature in the hairdryer.
D. It melts when the current in the hairdryer is greater than 10 A.
▶️Answer/Explanation
Answer: D. It melts when the current in the hairdryer is greater than 10 A.
Explanation: A fuse is a safety device that melts and breaks the circuit if the current exceeds a certain value (in this case, 10 A), preventing damage to the appliance or wiring.
Question
An electric kettle, washing machine and cooker are all switched on and connected through an extension cable into a single mains socket.
What is the electrical hazard of this arrangement?
A) The cooker overheats.
B) The extension cable overheats.
C) The kettle overheats.
D) The washing machine overheats.
▶️Answer/Explanation
Answer: B) The extension cable overheats.
Explanation: Connecting multiple high-power appliances to a single extension cable can cause the cable to overheat due to excessive current flow, posing a fire hazard.
Question
The table shows the usual current in each of four household appliances and the fuse used to protect each of them. The only fuses available are rated at 3 A, 5 A or 13 A. Which row shows an appliance that has been fitted with the most appropriate of the fuses available?
| Appliance | Current / A | Fuse rating / A | |
|---|---|---|---|
| A | Hairdryer | 5.5 | 5 |
| B | Kettle | 7.5 | 13 |
| C | Lawnmower | 5.0 | 3 |
| D | Slow cooker | 1.0 | 5 |
▶️Answer/Explanation
Answer: B Kettle
Explanation: The fuse rating should be slightly higher than the usual current to allow for small surges without blowing the fuse. For the kettle, a 13 A fuse is appropriate as it is higher than the usual current of 7.5 A.