units of electricity ashfield direct learning holly millar ks4 energy
TRANSCRIPT
Units Of Electricity
Ashfield Direct Learning
Holly Millar
Ks4 Energy
What are units of electricity?
Electrical Units are a measure of the electrical energy used.
An Electrical Meter (like the one you will have in your home) measures the amount of energy used in Kilo-watt hours.
Your meter at home may look like this………
The Kilowatt-hour
A kilowatt-hour is a unit of energy It is used in calculating domestic electricity bills and is
measured on a meter in the home REMEMBER: it is NOT a unit of power…..that is the
kilo-watt or watt!
Kilowatt-hour calculations…..
ENERGY TRANSFERRED (kWh) = POWER (kW) x TIME (h)
EXAMPLE :
a 2000W electric hot plate is switched
on for 90 mins……
E = P x t
= 2kW x 1.5 hours
= 3 kilowatt hours
E
P T
Examples of kilowatt-hours….
A 200 watt T.V set ……..transfers 1 kWh of energy if it is switched on for 5 hours
A 500 watt vacuum cleaner……..transfers 1kWh of energy if it is switched on for 2 hours