Question

A wire of radius R carries a current I. The current density is given by the function J = J0 (1 - r/R) where r is measured from the center of the wire and J0 is a constant. What is the value of J0 if I = 1A, R = 1.5 mm (in A/m2)?
A. 1.06 × 105
B. 2.12 × 10-5
C. 4.76 × 103
D. 3.18 × 10-1
E. 4.24 × 105