Hi this is my first post so please be nice :) 1. The problem statement, all variables and given/known data The problem has been set up that a circuit containing a resistor and switch is being driven by a power source of unkown potential. The switch is flick to short the power source leaving only the resistor in a closed loop. Calculate the current decay. Initial current = 100A Resistance = 1n[tex]\Omega[/tex] 2. Relevant equations V=IR Power = I2R 3. The attempt at a solution I'm not too sure. The power generated, and hence the heat loss can be found to be 1e-5W so thats 1e-5 Joules per second of heat loss. I'm not sure if we have enough information. Current decay involving inductance or capacitance is well known but just a resistor in a circuit of 'ideal' conductors? I'm assuming it is an exponential decay of form I=I0e-t/[tex]\tau[/tex] but finding the decay constant is proving tricky. Any advice???? Thanks in advance.