Solenoid Equation Help: Finding Current with Electron Motion

[KoGs]

Homework Statement

A long solenoid has 100 turns/cm and carries current i. An electron moves within the solenoid in a circle of radius 2.30 cm perpendicular to the solenoid axis. The speed of the electron is 0.04640c (c= speed of light). Find the current i in the solenoid



B = permeability constant * i * 100turns/cm for the solenoid without the electron.


I guess I need the speed of the electron somewhere.

F = ma
qvB = m (v^2)/r
So we can get B of the circular loop.

What do I do next? I don't suppose we just equate these two B's.

 

[OlderDan]

Homework Statement

A long solenoid has 100 turns/cm and carries current i. An electron moves within the solenoid in a circle of radius 2.30 cm perpendicular to the solenoid axis. The speed of the electron is 0.04640c (c= speed of light). Find the current i in the solenoid



B = permeability constant * i * 100turns/cm for the solenoid without the electron.


I guess I need the speed of the electron somewhere.

F = ma
qvB = m (v^2)/r
So we can get B of the circular loop.

What do I do next? I don't suppose we just equate these two B's.

There's an idea. The only thing around producing a field to bend the path of that electron is the solenoid.