Grade 9 Electricity

What happens to the resistance of an NTC thermistor as its temperature increases?

• Increases

• Decreases

• Stays the Same

• Becomes Infinite

Which component allows current to flow in one direction only?

• Resistor

• Diode

• Thermistor

• Relay

The purpose of a potential divider in a circuit is to:

• Divide current equally between components

• Reduce resistance in the circuit

• Provide a specific potential difference to a component

• Protect components from overheating

What is the function of a fuse in an electrical circuit?

• To convert electrical energy into heat

• To prevent overheating by breaking the circuit if current is too high

• To provide a pathway for current to the earth wire

• To amplify electrical signals

Damaged insulation in a mains cable may lead to:

• Reduced resistance in the circuit

• An increased risk of electric shock

• A short circuit, causing reduced voltage

• Proper functioning of the appliance

A mains circuit consists of which wires?

• Live, neutral, and resistor

• Live, earth, and capacitor

• Live, neutral, and earth

• Positive, negative, and ground

Why should a switch always be connected to the live wire?

• To ensure the circuit can handle more current

• To safely disconnect the appliance from the supply voltage

• To provide additional resistance in the circuit

• To protect the neutral wire from overheating

Which statement about damp conditions and electrical appliances is correct?

• Damp conditions have no effect on electrical appliances

• Damp conditions can cause electricity to leak, increasing the risk of shock

• Damp conditions increase the resistance of the circuit

• Damp conditions are safe for operating double-insulated appliances

The symbol for a light-emitting diode (LED) includes:

• Two parallel lines

• A triangle with a line across it and arrows pointing away

• A zigzag line

• A square box

The appropriate fuse rating for an appliance operating at 240 V and 3 A is:

• 2 A

• 3 A

• 5 A

• 10 A