To find the power formula on the electrical side you should have to know ohm's law of voltage that is V=I*R.
Here power formula is P=V*I.
Interms of resistance P=(IR)*I ==>I² R.
Here the power dissipated when 3.2 ampere of current flows through an 18-ohm resistor is
P=I² R ==>(3.2)² (18).
====>10.24(18)=184.32W.
W= Watts.
Watts is a unit of power.
Hope this helps