1. The problem statement, all variables and given/known data When would Ohm's law not be valid. Does Ohm's law only work with specific resistors, i.e. when R = 25 ohms? As the current flows and the resistor heats up does resistance change? 2. Relevant equations V = IR 3. The attempt at a solution I would say that no, Ohm's law is not going to be valid all the time. There are specific materials that are designed to be resistors and can handle a certain amount of current. I've been reading about diodes and I'm not really sure what they are, but I believe they do not hold true to Ohm's law. I also want to say that conductors and transistors do not apply to Ohm's law. From these conclusions, I think that as current flows and the resistor heats up, resistance does change because the resistor is meant to handle a certain work load. As those parameters change, the resistor would probably fail and resistance would lessen.