Question

How can a current be induced in a wire coil?A. By connecting the wire to a batteryB. By twisting the wire into the shape of a coilC. By placing the wire around a magnetO D. By moving a magnet into and out of the wire coilSUBM

Answer 1

According to Faraday's law of induction, a change in magnetic field induces a current in a wire and a current flowing in a wire causes a changing magnetic field. This is modeled by the following formula:

$\epsilon=-N\frac{\Delta\Phi}{\Delta t}$

Where:

$\begin{gathered} \epsilon=\text{ induced voltage} \\ \Delta\Phi\text{ = change in magnetic flux} \\ \Delta t=\text{ change in time} \\ N=\text{ number of turns of the coil} \end{gathered}$

Therefore, in order to induce the current, we need to move the magnet into and out of the coil. That way we create the change in the magnetic field that is required.