# Electric force with a moving conductive bar in a magnetic field

1. ### slain4ever

63
1. The problem statement, all variables and given/known data
A conducting bar is moved to the right in a magnetic field going into the page, an electric field is set up in the bar. Is this electric field upwards or downwards.

3. The attempt at a solution
i think that because a current is being induced in the bar you use the right hand rule but the current goes the other way in the thumb therefore the electric field is up the bar. Is this correct?

2. ### Andrew Mason

6,829
The electric field is given by:

$$\vec{E} = \vec{v} \times \vec{B}$$

So use the right hand rule for cross product (use the index finger for v and the middle finger for B and the thumb will give the direction of E).

AM

3. ### slain4ever

63
is that a yes, by the way i think you misunderstood, i use the right hand palm rule, not the flemming thing.

4. ### Andrew Mason

6,829
If you use the right hand two-finger-thumb rule to determine cross product, you will not be confused.

AM

Know someone interested in this topic? Share a link to this question via email, Google+, Twitter, or Facebook

Have something to add?