Protons And Magnetism

[PhysicsChick]

A stream of protons passes a given point in space at a rate of 10 E9 protons/second. What mafnetic fiel do they produce 2.0 m from the beam?
i think i would use
I= 1.6 E-19x10 E 9
and then
B=(permativity of free space x I)/(2pir) using 2.0 as r? am i totally off or close?[o)]

[gnome]

permittivity of free space = ε0 = 8.85 x 10-12 C2/Nm2

permeability of free space = μ0 = 4Π x 10-7 Tm/A

Are those close, or totally off?

In this case, you want μ0 (permeability), not ε0.