Answer to Question #51721 in Electricity and Magnetism for Samuel

Question

1. A cirrent flows in a wire of circular cross-section with the free electrons travelling with a mean drift velocity v. If an equal current flows in a wire of the same material but of twice theradius, what is the new mean drift velocity?
(A) v/4 (B) v/2 (C) 2v (D) 4v

2. A wire with resistance of 8.0Ω is drawn out through a die so that its new length is three times its original length. Find the resistance of the longer wire assuming that the resistivity and density of the material are unaffected by the drawing process.
(a) 72Ω (b) 60Ω (c)80Ω (d) 45Ω