1. B=F/Il
B=kI/r k=4pi.10^-7/2pi=2.10^-7
I=koren(Fr/kl)
r=0,03m
l=0,75m
I=100A
3. B1=Ik/r1
B2=Ik/r2
B1/B2=r2/r1
B2=B1.r1/r2
B2=0,6T
2. B=m'(glicerina)kI/r
r=kIm'/B
m'=0,999
r=0,2m