# Once a circular path has been obtain for the electrons, how will increasing current to the coils aff

1. Oct 19, 2014

### Eddie10

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

Once a circular path has been obtain for the electrons, how will increasing current to the coils affect that path? Use equation 1 and the fact that e/m is a constant for the electron.
2. Relevant equations
e/m = 2V/B^2r^2

3. The attempt at a solution

I'm unclear as to how to find a solution because I think that the circular path of electrons will grow brighter, or grow dimmer when more current, or less current is applied, once the electrons are in a circular path.

However, how can I use the given equation to prove this?

Note, I have not conducted any type of measurements or observations of any kind, as this is a pre-lab questionnaire that I am fulfilling to get credit.

UPDATE: I firmly believe that increasing the current to the coils will make the circle larger, once the circular path has been established prior to increasing said current.

However, how can I use the given equation to show this?

As an aside, increasing the magnetic field will make the circle smaller.

Last edited: Oct 20, 2014
2. Oct 20, 2014

### haruspex

Maybe I'm misguessing the set up, but I would have thought the coils in question were generating the magnetic field, so the last line of your post seems the relevant one.

3. Oct 20, 2014

### Eddie10

The set-up is going to be the traditional set-up used for the e/m experiment that is used at most universities.
The coils will generate a magnetic field, but what will increasing the current do to the circle once it is established?

I think the increased current will expand the circle and make it bigger, but I am unsure how to show this with my equation.

4. Oct 20, 2014

### haruspex

If the function of the coils is to generate a magnetic field, then increasing the current will increase the field, yes? And as you wrote, increasing the field will shrink the circle.