Work of electric current (energy)

W=UIt

Result unit: J (often kWh)

What it describes

The electrical energy consumed by a load over time t.

W

work (energy)

[J]

U

voltage

[V]

I

current

[A]

t

time

[s]

The energy consumed by a load is power times time (

W=Pt=UIt

). Energy meters measure it in kilowatt-hours (1 kWh = 3.6 MJ).

Electricity bills, energy consumption by appliances.

A 2000 W heater runs for half an hour. How much energy does it use?

Substitution

P=2

kW,

t=0.5

Result

W=2\cdot0.5=1

kWh

=3.6

MJ.

Found this formula useful? Share it.

It's free — send it to a friend who's revising.

Teaching? Embed this formula on your site.

Free widget — paste it on your school site, blog or notes. It links to the full version.