A Wire of Radius R Carries a Current I

Multiple Choice

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.Use Ampère's law to find the magnetic field inside the wire at a distance r < R from the axis.What is the magnitude of B if I = 1A,R = 1.5 mm,and r = 1 mm?

A) 12 mT
B) 37 µT
C) 1.5 T
D) 45 mT
E) 148 µT