Question

A long copper wire is used to transmit a current from one side of the campus to another as part of a scientific experiment to measure the speed of sound. The wire has a cross sectional area of 2.5*10^-6 m^2 and a total resistance of 7.2 ohms. A voltage of 25 V is applied across the length of the wire. The resistivity of copper is 1.68*10^-8 ohms m. How long is the wire? What is the current flowing through the wire?

Answer 1

-6 2 Silven, CA? cross sectional area of copper wire = 2.5x10m Resistance = 7.212 voltage applied tv) = 25V - CR) resistivity of copper be let the length of copper wire be Le cement through wine (1) wire = 1.68x108r-m. Resistance of wire with tengthu L cross section arend is given by CR) Rap L op - resistivity of wire) A we know R = 702 P = 1.68x108 L=? A = 2.5X10 m² 7.2 1068x 108 x L 2.5X106 = ) La 7.2x2.5X10 • 10. HX10 m 1.68X108 3 =1.0.7x10 m - 1.07 km 1.07 km] [length of wire = from chm's Law, V: IR -) 25 = 1 X 1.2 = = 3.47 A [current through wire (I) = 3-4724