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

1. Apr 11, 2011

### slain4ever

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. Apr 11, 2011

### Andrew Mason

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. Apr 12, 2011

### slain4ever

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

4. Apr 12, 2011

### Andrew Mason

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

AM