What is the electric field formula for a long line?

[akle]

Homework Statement

Hi. I want to calculate electric field radiated by 50 Hz transmission line (overhead power line). for this I'm thinking about Gauss law which can help. in this case I have formula E = lambda / 2*pi*eps0*r
where lambda is charge per unit length (unit: Coloumb / m).
the problem is that if I want to calculate electric field E, how I can get value for lambda ?... is there another formula for lambda ?

 

[akle]

Finally I've found that
by Ampers law: B = mu0*I / 2*pi*r
where B is magnetic field.
after several operation i.e using Gauss law, by Faraday's law
B = mu0*eps0*E*v
after that electric field becomes E= I / 2*pi*eps0*r*v
where v is prooved to be speed of light. I've tested also this formula by taking into account units,it worked!.
very cool. I realize that these people were really genios as I'm digging into subject :)