Building a solenoid

1. Jul 16, 2014

Ziggey

Hello so I just want to make sure I Am doing this correctly. also I know there is a magnetic field force formula. That is F= qv (dot) B
How would I go about using that formula with the magnetic field I created from the solenoid in the picture?

Thanks for any help!
Zig

2. Jul 16, 2014

Matterwave

It's really hard to read the text in the picture. Can you summarize by posting it?

3. Jul 16, 2014

Ziggey

Ok I'm using the equation B= unI
n=N/L
u=k(4*pie*10^-7)
k=200

Once I plug in the numbers I get n= 18/.504=35.7142, u= 2.513*10^-4.
So if I have 10 amps then my final number should be .0897 B. Did I do that correct?

4. Jul 17, 2014

PhysicoRaj

For the values you have assumed, the calculations seem correct. About the magnetic field force formula, you are referring to Lorentz force formula:$F=q (\vec{v}\times\vec{B})$

5. Jul 17, 2014

Ziggey

Ok well what I don't understand about that equation is the velocity part. I have been trying to do some reading on it, but I don't understand it. Is the velocity for the speed of the electron or something else?

6. Jul 17, 2014

Staff: Mentor

7. Jul 18, 2014

Ziggey

Ok I will try and get it then show my work to make sure I'm doing it correctly. Thank you for the help!! Zig