What is the primary reason AC (alternating current) is used for generating and distributing electricity?

• It is more efficient and convenient than DC (direct current).

• It is safer than DC.

• It is cheaper to produce than DC.

• It can only be used in domestic properties.

Answer explanation

AC is used for generating and distributing electricity because it is more efficient and convenient than DC.

What device increases the voltage of electricity as it leaves the power station?

• Isolation switch

• Step-up transformer

• Step-down transformer

• Electricity meter

Answer explanation

A step-up transformer increases the voltage of electricity as it leaves the power station, making it suitable for long-distance transmission before being stepped down for consumer use.

What is the purpose of the main fuse in a domestic electricity supply system?

• To measure how much energy is being consumed

• To provide protection to the property by ensuring only a set amount of current can flow into it

• To distribute electricity to various circuits

• To monitor and cut the power in case of an electrical fault

Answer explanation

The main fuse in a domestic electricity supply system provides protection by ensuring only a set amount of current can flow into the property, preventing overload and potential hazards.

What does an RCD (Residual Current Device) do?

• Converts AC to DC

• Cuts the power if the current in the phase line is not equal to the current in the neutral line

• Measures the amount of electricity used

• Increases the efficiency of electricity distribution

Answer explanation

An RCD (Residual Current Device) cuts the power if the current in the phase line is not equal to the current in the neutral line.

What is the typical function of an MCB (Miniature Circuit Breaker)?

• To protect circuits from overload and short circuit

• To step down the voltage for domestic use

• To isolate the property from the electricity supply

• To convert electricity from single-phase to three-phase

Answer explanation

The typical function of an MCB is to protect circuits from overload and short circuit, making it the correct choice.

How is electricity typically distributed from the substation to a domestic property?

• Through a series of batteries

• Via wireless transmission

• Using solar panels

• Through overhead or underground cables

Answer explanation

Electricity is typically distributed from the substation to a domestic property through overhead or underground cables, not through batteries, wireless transmission, or solar panels.

What is the main difference in the electricity supply system between North America and countries like the UK, Europe, and Australia?

• North America exclusively uses underground cables

• North America does not use electricity meters

• North America uses two voltages in homes

• North America uses DC instead of AC

Answer explanation

The main difference is that North America uses two voltages in homes, unlike the UK, Europe, and Australia.

What does the phase and neutral wire do in a service cable?

• They are not used in modern electrical systems

• They are used for telephone connections

• They carry the electricity into the property

• They connect the property to the internet

Answer explanation

The phase and neutral wire carry the electricity into the property, making them essential components of the service cable.

What might cause an RCD to trip?

• A perfectly balanced current in phase and neutral lines

• Turning off all electrical appliances in the home

• A difference in current between the phase and neutral lines indicating a fault

• A decrease in electricity demand

Answer explanation

An RCD trips when there is a difference in current between the phase and neutral lines, indicating a fault in the electrical system.

What is the purpose of the earth wire in a domestic electrical system?

• To carry excess electricity back to the power station

• To provide a path for electricity in case of a fault, reducing the risk of electric shock

• To increase the efficiency of electrical appliances

• To measure the consumption of electricity

Answer explanation

The earth wire in a domestic electrical system provides a path for electricity in case of a fault, reducing the risk of electric shock.