Understanding Electricity and Energy Units

The video tutorial explains electrical power as the rate of work done, measured in watts, and how energy is calculated using power and time. It introduces the kilowatt hour as a more practical unit of energy for larger applications like household devices. The tutorial covers the conversion between joules and kilowatt hours and explains how kilowatt hours are used in electricity bills, often referred to as 'units'. It also discusses the cost per unit and how to calculate the total cost of electricity usage.

What is the SI unit of power?

• Watt

• Kilowatt-hour

• Joule

• Newton

What is the relationship between power, work, and time?

• Time = Power x Work

• Power = Work / Time

• Work = Power x Time

• Work = Power / Time

How is energy measured when power is in watts and time is in seconds?

• In kilowatt-hours

• In joules

• In newtons

• In calories

What is a more practical unit of energy for household devices?

• Watt

• Kilowatt-hour

• Newton

• Joule

Why is the kilowatt-hour a more useful unit for measuring energy in households?

• Because it is smaller than a joule

• Because it is easier to convert to watts

• Because household devices often use power over longer periods

• Because it is the SI unit of energy

How many joules are equivalent to one kilowatt-hour?

• 3,600 joules

• 1,000 joules

• 3.6 x 10^6 joules

• 10^6 joules

What is often referred to as 'units' in household electricity bills?

• Kilowatt-hours

• Watts

• Newtons

• Joules

What does a household electricity bill typically show instead of kilowatt-hours?

• Joules

• Units

• Newtons

• Watts

How can you calculate the total cost of electricity usage?

• Multiply the number of units by the cost per unit

• Add the number of units to the cost per unit

• Divide the number of units by the cost per unit

• Subtract the cost per unit from the number of units

What is the cost range per kilowatt-hour mentioned in the video?

• 25 to 35 pence

• 5 to 15 pence

• 1 to 5 pence

• 15 to 25 pence