Hello! I have a few questions that need answers. They are just simple thoughts. First of, its is said that the formula P = UI can applied to the energy being transformed every second over any component. But the formula P = (U^2)/R and the P= (I^2)R only can be applied over resistors. But I think that the two formulas can I fact be applied to any component as well, as long as we know the resistance R of that component there really is no difference. The only difference may be that not all of the energy goes to waste as heat in other components that are not resistors. Am I right? Secondly, when one connects a spot of a circuit to earth that spot and only that spot gets the electrical potential zero. It does not affect other parts of the circuit that are located behind that point of grounding. But from that point and forward a positive test charge will not get affected of any electrical field that is located behind the spot, it will only be affected by new electrical fields located forward counting from the spot. Why is that?