A charge of #12 C# passes through a circuit every #4 s#. If the circuit can generate #8 W# of power, what is the circuit's resistance?

1 Answer
Sep 27, 2016

I got: #0.9Omega#

Explanation:

Here we have a current #I# of charge passing through the circuit in a given time, or:
#I="charge"/"time"=12/4=3A#
The power is energy delivered by our charges (passing in the circuit) at each second.
We can write power in general as:
#P=VI# But here we take advantage of Ohm's Law, #V=RI#, to rearrange our expression of Power to include resistance as:
#P=I^2R#
so that:
#R=P/I^2=8/9=0.89=0.9Omega#