I still cant figure this thing out. It seems to me that thereare to many unknowns and I don't know where to start. Can somebodygive me a step by step walkthough of the problem using differentvalues? A wire of initial length L0 and radiusr0 has a measured resistance of 1.5 ohms. The wire is drawn under tensile stressto a new uniform radius of r = 0.20r0. What is the newresistance of the wire? I still cant figure this thing out. It seems to me that thereare to many unknowns and I don't know where to start. Can somebodygive me a step by step walkthough of the problem using differentvalues? A wire of initial length L0 and radiusr0 has a measured resistance of 1.5 ohms. The wire is drawn under tensile stressto a new uniform radius of r = 0.20r0. What is the newresistance of the wire?
Explanation / Answer
the length of the wire L = Lo and the radisu of the wire r = ro resistance R = 1.5 . the resistance of the wire R = L / A = L / 2r R 1 / r if the new radius = r = 0.20ro ro = r / 0.20 then the new resistance R' 1 / 0.20ro R ' 0.20(R) hence the resistivity decreases by 0.20 times theinitial resisistance.