Electrons in a beam of televison tube

1. Mar 18, 2005

Gonger

Ive got a question where I have to find the acceleration of a single electron due to the magnetic field. Now here is what I did. I tired to find Velocity using KE = .5mv^2. Solving for v. Then knowing that F=qvB and F=ma I made the equation qvb/m=a. But I cant get this to work. Is there some thing that I'm doing wrong. This is a related question with the numbers in it:
I think my problem is with converting uT to T for the electric field. And converting my 24 keV to J. Anyone have some help. Thanks.

2. Mar 18, 2005

Andrew Mason

Your approach is correct except that the force is:

$$\vec F = q\vec v \times \vec B = qvBsin\theta$$

What is the angle of $\vec v$ to the magnetic field?$\vec B$ Why not show us what you have done? It is a little hard to figure out where you may have gone wrong otherwise.

AM

3. Mar 18, 2005

witze

Well, the vertical component of B was given in the problem, so I don't think you need to do the cross product. You're probably just having problems with unit converstions.