What is motional emf?

Answer 1

Induced Current and Motional Emf

The electric field in the metal bar causes a potential difference of V = El = vBl. If the bar slides along metal rails, as in the figure below, a closed circuit is set up with current flowing in the counterclockwise direction, up the bar and then around the metal rail back to the bottom of the bar. TInduced Current and Motional Emf

The electric field in the metal bar causes a potential difference of V = El = vBl. If the bar slides along metal rails, as in the figure below, a closed circuit is set up with current flowing in the counterclockwise direction, up the bar and then around the metal rail back to the bottom of the bar. This is called an induced current.

The moving bar is a source of an electromotive force, called motional emf, since the emf is generated by the motion of the bar.

The force is defined as:

The magnitude of the induced emf can be increased by increasing the strength of the magnetic field, moving the bar faster, or using a longer bar.

Example

A bar of length 10 cm slides along metal rails at a speed of 5 m/s in a magnetic field of 0.1 T. What is the motional emf induced in the bar and rails?

Now that we've defined motional emf, solving this problem is simply a matter of plugging numbers into the appropriate equation:

his is called an induced current.