A very long straight wire has charge per unit length 1.4410-10C/m. question: At what distance from the wire is the magnitude of the electric field equal to 2.45 N/C? Use 8.85x10-12c/(N*m) for the permittivity of free space, and use =3.14. A very long straight wire has charge per unit length 1.4410-10C/m. question: At what distance from the wire is the magnitude of the electric field equal to 2.45 N/C? Use 8.85x10-12c/(N*m) for the permittivity of free space, and use =3.14.