Why does a thin wire melt and a thick wire glow when put up to the terminals? Explain in terms of resistance and current. Thanks=]
The higher the resistance the more heat will be generated in the wire. A thin wire has a higher resistance in comparison with a thick wire of the same material in the inverse proportion to their cross sections (as long as the length remains constant).
Everything has a temperature at which it will melt. Every conductor also has a resistance, which is just like it sounds, a wire sort of resists the electricity passing through it by heating itself up. If a wire's resistance causes it to heat up so much that it melts, either the wire is too thin, or there is too much current passing through it, or both. A thicker wire can handle the same current without heating up so much that it melts. Sorry I don't have any formulas for you, but I think you should understand it now.
A thin wire has a fairly good resistance to the flow of electricity, represented by say R ohms. Let V volts be the voltage across the terminals of a battery. The current I that flows through the resistance is given by I = V/R amperes, heat generated is V X I = V^2/R Now the internal resistance of a battery is very low and hence if R is in a certain range, I can be fairly high and the heat generated in the wire can be high enough to melt the wire. This is the concept used in a fuse to protect the remaining circuit from a melt down or a fire! When you use a thick wire, the resistance R is very low and hence a heavy current flows through the wire and makes it red hot.
the electrical restistance of a thin wire is greater that the tick wire. thus : Watt = current * current * resistance if the resistance of the thick wire is 10 times the resistcance of the thin wire , then ( with same voltage ) you have for small wire Watt = current * current * resistance for thick wire Watt = 10*current * 10*current * (resistance/10) = 10current current resistance. so the power generated in the thick wire is ten times more than the power in the thin wire ( if you keep the voltage the same ) so that is not why the smaller one melts. I dont know why it melts then, interesting
Sorry but that's not exactly the case. The thin wire actually burned thru because you exceeded it's ability to carry the current of the circuit that you connected to it. The thick wire glowed for the same reason. You probably have a short circuit in the device that the terminals are on. It would be impossible to address the resistance and current with the limited information that you have given us.
