- #1

Karagoz

- 52

- 5

## Homework Statement

This is taken from a problem with its solution. But there's one thing I didn't understand with the solution:

A closed conductor loop is located perpendicular to the field lines in a homogeneous magnetic field

*B*. The conductor slice CD is first in rest. Then we pull a constant force

*F*to the right. See figure above. The absolute value of the force is 1.8 N. The conductor slice slides without friction.

After a while the speed

*v*is constant and is equal to 4.0 m/s. The length of the conductor slice CD is 12 cm.

The electrical power in the circuit is given by:

The effect of the pull force F is given by: P = F*v

Since we do not have friction, these powers must be the same. And this gives:

How is it that the effect on the pull force P = F*v is equal to the electrical power in the circuit given by:

What's the proof?

## Homework Equations

P = F*v

P = ε^2/R = (vBl)^2/R