A coaxial cable consists of an inner cylindrical conductor of Radius R1=0.040m on the axis of an outer hollow cylindrical conductor of inner radius R2=0.080m and outer radius=0.090m. The inner conductor carries current I2=1 A in one direction and the outer carries I2=5A in the opposite direction. What is the value of the magnetic field at the following distances from the axis of the cable ?
a) at r=0.060m (in the gap midway the two conductors ) ?
b) at r=0.150m (outside the cable ) ?
Note U0=4pi *10^(-7) A