Let’s measure precisely how much electromotive force the generator can produce. The amount of electromotive force is measured in volts. In fact, electromotive force is sometimes referred to as voltage. Use a digital multimeter to measure the voltage of your generator. Connect the free ends of the probe wires to the wires coming out of the generator. What is the voltage reading when the generator is idle (i. e. when the crank is not being turned?)

fem = 0

Explanation:

The electromotive force is given by Faraday's law

         fem = - d / dt

where \phi _{B} is the flux of the magnetic field

The low magnetic flux is

         \phi _{B} = B. A = B A cos θ

substituting

      fem - d (B A cos θ) / dt

therefore for an electromotive force to exist there must be a change with respect to the time of

* The magnetic field

* The area waxed by the loop

* the angle between the magnetic field and the normal loop

* Any combination of the above

In this case, as the generator is stopped (inactive), there is no change in the parameters, therefore the electromotive force is zero (fem = 0).

b.a device that inputs heat into a cool object