A charge of #6 C# passes through a circuit every #3 s#. If the circuit can generate #18 W# of power, what is the circuit's resistance?

1 Answer

#4.5\ \Omega#

Explanation:

The electric current #I# is the rate of flow of charge w.r.t. time which given as

#I={dQ}/{dt}#

#=\frac{6}{3}#

#=2\ A#

If #R\ \Omega # is the electric resistance then the electric power or rate of heat generation is given by Joule's Law as follows

#H=I^2R#

#18=2^2R\quad (\because \ H=18\ W)#

#R=18/4#

#R=4.5#

Hence the electric resistance is #R=4.5\ \Omega#