The electric field in a 19 mm 19 mm square tungsten wire is

The electric field in a 1.9 mm 1.9 mm square tungsten wire is 0.012 N/C. What is the current in the wire? in A.

Solution

the resistance is expressed as follows:

          R = L/A

for tungsten: = 5.6*10^-8 .m

A = (1.9)² *10^-6 = 3.61*10^-6 m²

resistance is,

       R = (5.6*10^-8 *L) /3.61*10^-6

the voltage is:

       V = E*L = 0.012 * L

current is,

             i = V/R = [ 0.012 * L] /[(5.6*10^-8 *L) /3.61*10^-6] = 0.7735 A