gcsescience.com 6 gcsescience.com
What is Power?
Power is an amount of energy supplied in a certain time.
Power is measured in watts. Energy is measured in joules.
1 watt = 1 joule per second.
The word "per" means "divided
so power = energy ÷ time. P = E ÷ t.
volt = 1 joule per coulomb
and 1 amp = 1 coulomb per second
= volts x amps,
or power = voltage x current
P = V x I
This equation is important!
The above equation
rearranged to give
I = P ÷ V and V = P ÷ I
On the next page we shall see how to calculate the power
of any electrical component using a lamp as our example.
We can rearrange power =
energy ÷ time
to give energy = power x time. E = P x t.
Since power =
voltage x current (see above)
if we write V x I instead of P
in the above equation we get E = V x I x t.
energy = voltage x current x time.
See all equations for electricity.
Links Electricity Revision Questions
gcsescience.com Physics Quiz Index Electricity Quiz gcsescience.com
Home GCSE Chemistry GCSE Physics
Copyright © 2015 gcsescience.com. All Rights Reserved.