Chapter 18: Practical Electricity Part 2

Multiple Choice

Which is the correct relationship between energy(E), current(I) and resistance(R)?

• E = I + R
• E = R / I
• E = I^2 * R
• E = I * R^2

Multiple Choice

What does the fuse ratings tell us?

• The maximum current a fuse can handle before blowing.
• The voltage rating of a fuse.
• The minimum current a fuse can handle before blowing.
• The type of material used in the fuse construction.

Multiple Choice

What may cause damaged insulation?

• Physical wear and tear, moisture exposure, pest infestations, extreme temperatures, improper installation.
• Using high-quality materials
• Regular maintenance checks
• High humidity levels

Multiple Choice

Damaged insulation expose the wire and damaged insulation may lead to

• Enhanced wire durability
• Increased risk of electrical shorts, fires, or electric shocks.
• Lower energy consumption
• Improved insulation performance

Multiple Choice

Ovet-heating of cables is an electrical hazard due to

• Environmental factors like humidity.
• Low voltage operation of cables.
• Excessive current flow generating heat.
• Insulation failure causing sparks.

Multiple Choice

Overloading a power socket may lead to

• Fire hazards and equipment damage
• Enhanced connectivity options
• Improved device performance
• Increased energy efficiency

Multiple Choice

What can be the electrical hazard in a damp environment?

• Electric shock risk due to water conductivity.
• Enhanced conductivity of non-metal materials.
• Improved insulation properties of wires.
• Increased battery life of devices.

Multiple Choice

Which of the following can conduct electricity?

• Water at freezing temperatures conducts electricity.

• Pure water without impurities conducts electricity.

• Water with dissolved salts or minerals conducts electricity.
• Distilled water with no minerals conducts electricity.

Multiple Choice

What are the names of the 3 cables found in a 3-pin plug?

• ground wire
• positive wire
• return wire
• live wire, neutral wire, earth wire

Multiple Choice

Which cable has the highest potential? Live, Neutral and Earth.

• Ground
• Neutral
• Live
• Return

Multiple Choice

Which cable(s) has/have zero potential? Live, Neutral and Earth.

• Neutral and Earth
• Live and Earth
• Only Live
• Live and Neutral

Multiple Choice

What is the main function of the neutral wire?

• To increase the voltage in a circuit.
• To provide insulation for electrical wires.
• The main function of the neutral wire is to provide a return path for electric current.
• To act as a fuse in case of overload.

Multiple Choice

Which wire does the fuse connect to?

• Neutral wire
• Ground wire
• Earth wire
• Live wire

Multiple Choice

Which wire does the circuit breaker connect to?

• Ground wire
• Neutral wire
• Control wire
• Live (or hot) wire

Multiple Choice

Which wire does the switch connect to?

• Data wire
• Live wire
• Ground wire
• Neutral wire

Multiple Choice

Why do birds not get an electrical shock when they perch on electrical cables?

• Birds have special feathers that insulate them from electricity.
• Birds are immune to electrical currents due to their size.
• Birds can sense electrical fields and avoid them.
• Birds do not get shocked because they are not completing an electrical circuit.

Multiple Choice

For an electric kettle that has a power rating of 2200 W and an operating voltage of 240 V, what should be the value of the fuse used?

• 10 A
• 5 A
• 15 A
• 20 A

Multiple Choice

What is the advantage of using a circuit breaker than using a fuse?

• The advantage of using a circuit breaker is that it can be reset and reused, while a fuse must be replaced after it blows.
• Circuit breakers are less reliable than fuses.
• Fuses can be reset and reused like circuit breakers.
• Circuit breakers are cheaper than fuses.

Multiple Choice

What is the advantage of using a fuse over a circuit breaker?

• Fuses are generally simpler, cheaper, and easier to replace than circuit breakers.
• Circuit breakers are more cost-effective than fuses.
• Fuses provide better protection against overloads than circuit breakers.
• Fuses can be reset multiple times without replacement.

Multiple Choice

Why do we connect the earth wire to the metal casing of an electrical applicance?

• To increase the voltage of the appliance.
• To enhance the appliance's performance.
• To improve the aesthetic appearance of the appliance.
• To prevent electric shock and ensure safety by directing fault currents to the ground.