The video tutorial explains how electrical energy is measured in kilowatt hours and joules. It provides formulas for calculating energy transferred, using examples of a 2 kilowatt electrical fire and a 20 watt lamp. The tutorial also covers how electricity meters measure usage and how to calculate the cost of electricity based on units consumed.

What is the formula to calculate energy transferred in kilowatt hours?

• E = P + t, where P is in kilowatts and t is in hours

• E = P × t, where P is in watts and t is in seconds

• E = P × t, where P is in kilowatts and t is in hours

• E = P / t, where P is in kilowatts and t is in hours

If a 2 kilowatt device is used for 5 hours, how much energy is consumed?

• 7 kilowatt hours

• 12 kilowatt hours

• 5 kilowatt hours

• 10 kilowatt hours

How is energy calculated in joules?

• E = P × t, where P is in kilowatts and t is in hours

• E = P × t, where P is in watts and t is in seconds

• E = P + t, where P is in watts and t is in seconds

• E = P / t, where P is in watts and t is in seconds

A 20 watt lamp is lit for 200 seconds. How much energy does it transfer?

• 5,000 joules

• 4,000 joules

• 3,000 joules

• 2,000 joules

If electricity costs 8 pence per unit, what is the total cost for using 5 units?

• 40 pence

• 50 pence

• 30 pence

• 20 pence