# Left-hand rule

1. Jan 16, 2005

### Reshma

Can someone explain me the left-hand rule in Electrodynamics?

2. Jan 17, 2005

### Moneer81

Reshma,

the left hand rule, known as Fleming's left hand rule, is used to predict the motion of a wire carrying current when the wire is placed in a magnetic field. As you know, the current in the wire will induce a magnetic field and that magnetic field will react with the magnetic field of the magnet. the left hand rule helps you predict the movement of the wire.

Point your thumb straight out, and use your first finger to point in the direction of the magnetic field, and your second finger in the direction of the current. Your thumb will be pointing in the direction of the force experienced by the wire.

visit www.le.ac.uk/se/centres/sci/selfstudy/mam12.htm for a visual illustration (reference)

3. Jan 17, 2005

### dextercioby

$$\vec{F_{em}}=I\vec{B}\times \vec{l}$$

where $\vec{l}$ has the sense of the current.
Accidents may happen and people may lose their fingers...The cross product may be forgotten...But,hey,Fleming's stupid rule may be forgotten as well.

Daniel.

4. Jan 19, 2005

### Reshma

Thanks for the help :-)

5. Jan 19, 2005

### Staff: Mentor

I think you meant:
$$\vec{F_{em}}=I \vec{l}\times \vec{B}$$