I am just scraping the surface of electromagnetic induction, and I have some questions. First, let me illustrate what I know. I know that in a simple circuit with a battery and a switch, when the switch is turned on, a current flows which produces a magnetic field of strength in proportion to the amps of the current. Now, the reverse scenario. I know that when you have a circuit and a magnet, if the magnet moves around near the circuit, a current is produced, and Faraday's law tells us how much voltage is produced. However, this is confusing to me. What is the point of Faraday's law in telling us how much voltage is produced when there is a battery connected to the circuit with a specified amount of voltage? Does Faraday's law imply that we don't need a battery since the magnet supplies the electromotive force necessary to start a current? Finally, if a battery IS needed for electromagnetic induction, then how does the magnet interact with the battery to elicit an emf that is stipulated by Faraday's law?