Electricity in the Home Quiz

What is the unit used to measure the amount of energy used in the home?

• Joule

• Kilowatt-hour (kWh)

• Ampere

• Volt

Which equation is used to calculate the cost of electricity used in the home?

• Cost = Power × Time

• Cost = Units used × Cost per unit

• Cost = Voltage × Current

• Cost = Resistance × Current

What is the main difference between Alternating Current (AC) and Direct Current (DC)?

• AC has a constant size and direction, DC changes direction

• AC is supplied by batteries, DC is supplied by the National Grid

• AC voltage and current constantly change size and direction, DC voltage and current have a constant size and direction

• AC is only used in small devices, DC is used in homes

Which type of current is supplied by the National Grid?

• Direct Current (DC)

• Alternating Current (AC)

• Both AC and DC

• Neither AC nor DC

Which wire in a ring main circuit carries a current into the house at a high voltage?

• Earth

• Neutral

• Live

• Ground

What is the purpose of the earth wire in a ring main circuit?

• To carry current into the house

• To complete the circuit

• To connect the casing of a device to the ground for safety

• To increase voltage

What does a fuse do in an electrical circuit?

• Increases the current if it becomes too low

• Stops the current if it becomes too large by melting a wire

• Changes AC to DC

• Increases the voltage

Which safety device reacts most quickly and can be reset after tripping?

• Fuse

• Miniature circuit breaker (MCB)

• Residual current circuit breaker (RCCB)

• Earth wire

What is one advantage of a ring main circuit in a home?

• It uses only one wire for all devices

• The current can travel two ways, allowing thinner wires and lower current in each part

• It increases the voltage to all sockets

• It prevents the need for safety devices

How is the efficiency of a device typically shown?

• By its color

• On a scale, with a higher rating indicating greater efficiency

• By the number of wires it uses

• By its voltage