Final answer:
To light up an LED using a bar magnet and a coil of wire, you apply Faraday's law of electromagnetic induction by moving the magnet in and out of the coil to generate electricity that powers the LED.
Step-by-step explanation:
To cause the LED to emit light using a powerful bar magnet, a spool of insulated wire, and the LED, you can employ the principle of electromagnetic induction as described by Faraday's law. First, you would wrap the wire around a core to create a coil. Then you would quickly move the bar magnet in and out of the coil, or alternatively, move the coil around a stationary magnet.
This movement of the magnet relative to the coil will generate electricity due to the changing magnetic field, which induces an electrical current in the coil. This current can then flow through the LED, causing it to light up. Remember, the movement has to be continuous because once the relative motion stops, the flow of electricity will also cease, and thus the LED will turn off.