Magnetic field in a tv set

shaffeb · Mar 13, 2007

1. The problem statement, all variables and given/known data
In a television set, electrons are accelerated from rest through a potential difference of 19kV. The electrons then pass through a 0.28T magnetic field that deflects them to the appropriate spot on the screen. Find the magnitude of the maximum magnetic force that an electron can experience.

2. Relevant equations

F=qvBsin(theta)
E=-V/x

3. The attempt at a solution
I am trying to figure out where the potential difference comes into play but am not sure because E and x are not given. Any hints would be great, thanks.

chaoseverlasting · Mar 14, 2007

When the electrons are accelerated across the potential given, they gain kinetic energy =eV, where e is the charge on the electron. Using this, you can find the speed of the electron once it leaves the electric field and enters the magnetic field.

Then, the maximum magnetic force will be when sin(theta)=1. The speed you know, the magnetic field strength you know, and q=e=charge on electon. Solve for F.

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Magnetic field in a tv set

shaffeb

chaoseverlasting