I am working through a book of problems and am confused by the answer to this one:
A 12 V battery supplies 60 A for 2 seconds.
The total resistance of the wires in the circuit is 0.01 Ohm.
Q1. What is the total power supplied?
Q2. What is the energy lost as heat in the wires?
Total power output = 12 * 60 * 2 = 1440 Joules.
All good so far.
This is the answer in the book:
P = I²R * t = 3600 * 0.01 * 2 = 72 Joules
That's fine with me. However, if I use the equivalent equation P=V²/R ...
P = V²/ R * t = 12² / 0.01 * 2 = 28,800 Joules
Both of these equations are for P, so how are they giving me different answers?