# What is the force on an electron traveling parallel to the wire

1. Mar 11, 2009

### stonnn

1. Two parallel wires 0.200 m apart carry currents in opposite directions of 5.00 A. Find the
magnetic field between the wires 0.0500 m from one of them and 0.150 m from the other.

2. A long straight wire carries a current of 100. A.
a. What is the force on an electron traveling parallel to the wire, in the opposite
direction to the current, at a speed of 2.50x106 m/s when it is 0.100 m from the
wire?

Attempt: F=qvB

b. Find the force on the electron under the above circumstances when it is traveling
perpendicular to the wire.
electronic charge 1.602x10-19 C

2. Mar 11, 2009

### LowlyPion

Re: Magnetism

Just writing the Lorentz Force law isn't really an attempt.

How would you think to approach it?

3. Mar 11, 2009

### stonnn

Re: Magnetism

for the first one, do we just get the magnetic field total? This is what i did.

Btotal = B1 + B2
B1 = MoI/2IIr ---> [(1.26X10^-6)(5)/(6.28)(15)
B2 = MoI/2IIr ---> [(1.26x10^-6)(5)/(6.28)(0.05)

Is that right?

for the second one, I calculated magnetic field first. Then, used this equation:

F=qvb
Magnetic force faces the positive x direction, right? Im still kinda confused about the right hand rule

b. Magnetic force faces in the negative y direction?

please let me know if im wrong about anything. Thanks !

4. Mar 11, 2009