The heat dissipated by a current-carrying conductor (Joule–Lenz law).
Symbols
Q
heat
[J]
I
current
[A]
R
resistance
[Ω]
t
time
[s]
Where it comes from
Current flowing through a resistor dissipates heat proportional to the square of the current — that is why overloaded wires heat up. It is the operating principle of heaters and fuses.
When to use it
Heaters, resistive heating, energy losses in wires.
Example
A current of 2 A flows through a 10 Ω resistor for 30 s. Calculate the heat dissipated.