CIE iGCSE Co-Ordinated Science P4.4 Electrical safety Exam Style Questions Paper 2
▶️ Answer/Explanation
A fuse must have a rating slightly higher than the normal operating current, so it does not blow during normal use.
Since the kettle draws 9.0 A, any fuse rated below this (1 A, 3 A, or 8 A) would blow immediately during normal operation.
The 13 A fuse is the smallest standard rating that is still safely above 9.0 A, making it the most appropriate choice.
✅ Answer: (D)
Since the kettle draws 9.0 A, any fuse rated below this (1 A, 3 A, or 8 A) would blow immediately during normal operation.
The 13 A fuse is the smallest standard rating that is still safely above 9.0 A, making it the most appropriate choice.
✅ Answer: (D)
▶️ Answer/Explanation
A fuse contains a thin wire that melts and breaks the circuit if the current becomes too large.
This protects the circuit and appliance from damage or fire caused by excessive current, such as from a fault.
A fuse does not regulate current or voltage to a constant value — it simply disconnects the circuit when overloaded.
✅ Answer: (B)
This protects the circuit and appliance from damage or fire caused by excessive current, such as from a fault.
A fuse does not regulate current or voltage to a constant value — it simply disconnects the circuit when overloaded.
✅ Answer: (B)
▶️ Answer/Explanation
A fuse must be placed in the live wire, so that when it melts it disconnects the dangerous high-potential supply from the appliance.
A fuse does not produce a fixed or minimum current; it melts and breaks the circuit once \(I > 3.0\text{ A}\) (its rated value).
✅ Answer: (A)
A fuse does not produce a fixed or minimum current; it melts and breaks the circuit once \(I > 3.0\text{ A}\) (its rated value).
✅ Answer: (A)
▶️ Answer/Explanation
A fuse protects a circuit by melting and breaking the circuit if the current becomes dangerously high, preventing overheating and fire — it does not maintain a constant current.
The fuse rating must be just above the normal operating current of 10 A, so a 13 A fuse is suitable (a 9 A fuse would blow immediately during normal use).
This matches “protects from overheating” with a 13 A rating.
✅ Answer: (D)
The fuse rating must be just above the normal operating current of 10 A, so a 13 A fuse is suitable (a 9 A fuse would blow immediately during normal use).
This matches “protects from overheating” with a 13 A rating.
✅ Answer: (D)
▶️ Answer/Explanation
A fuse must have a current rating higher than the normal operating current of the appliance, so that it does not blow during ordinary use.
Since the heater draws 11A, a 3A or 10A fuse would melt (blow) even under normal conditions, disconnecting the heater unnecessarily.
A 13A fuse is the smallest standard rating above 11A, so it lets the heater run normally but still melts quickly if a fault causes an excessive current, making it the most appropriate choice (36A would be far too high to offer proper protection).
✅ Answer: (C)
Since the heater draws 11A, a 3A or 10A fuse would melt (blow) even under normal conditions, disconnecting the heater unnecessarily.
A 13A fuse is the smallest standard rating above 11A, so it lets the heater run normally but still melts quickly if a fault causes an excessive current, making it the most appropriate choice (36A would be far too high to offer proper protection).
✅ Answer: (C)