# Field of a moving eletron

1. May 22, 2008

### gstrosx

1. The problem statement, all variables and given/known data

An electron is moving with a speed of 3*10^6 m/s. What are the directions (NE, N, NW,..., In the screen, out of the screen, zero magnitude) of the electric and magnetic field. What is the magnitude of the electric and magnetic field?
Code (Text):

moves this direction 3e6
/
/ angle = 60 degrees
electron-------------------------Observation location, d = 3e-10

2. Relevant equations

for field direction the right hand rule is applicable

E=N/C
B=T

3. The attempt at a solution
Efield is similar to a Efield from a electric circuit, applying the right hand rule in the opposite direction of the movement of the electron gives out of the screen.

Mfield is, at a speratic guess (using a left hand rule i think) is East

|E|=1/4pi epsilon naught * chargeOfelectron/d^2

|B|=googly eyes.

2. May 22, 2008

### foxjwill

You're confusing the direction of the E-field with that of the B-field. Remember that the E-field due to a point charge is
$$\textbf{E}=\frac{Q}{4\pi \epsilon_0 r^2}\ \hat{\textbf{r}}$$​
and the B-field due to a point charge is
$$\textbf{B} = \frac{\mu_0}{4\pi} \frac{q\textbf{v} \times \hat{\textbf{r}}}{r^2}$$​