Problem 2
A uniform wire of length L and constant cross-sectional area A has resistivity ρ at fixed temperature. Its ends are connected to an ideal constant-voltage source V; take ρ unchanged by heating, with steady current and no leakage. (a) Find wire resistance R from resistivity. (b) Calculate current I and current density J. (c) Find Joule power P and describe its dependence on L when V,A,ρ are fixed. Use SI units throughout and treat components as ideal exactly as specified. State sign conventions when writing equations and retain units in final results.
problems.proof.stepOf
problems.proof.analysis
Substitute the established relation and isolate the requested quantity. Keep the physical solution consistent with the initial conditions and assumptions.