B = uo.I
_____
2πa
Bp = Ba - Bb
Bp = uo.I uoI
____ . ____
2πa 2πa
Bp = 4π.10^-7. 20 -4.π.10^-7.20
____________. _____________
2π.2.10^-2 2π.6.10^-2
Bp = 20.10^-7 -2.20.10^-7
_________ . __________
10^-2 36.10^-2
Bp = 20.10^-7.10^2 - 6,7.10^-7.10^2
Bp = 20.10^-5-6,7.10^-5
Bp = 13,3.10^-5. 10^3
Bp = 13,3.10^-2
Bp = 0,13 militesla