Question

You have a light bulb, a bar magnet, a spool of wire that you can cut into as many pieces as you want, and nothing else. How can you get the bulb to light up? a) You can't. The bulb needs electricity to light it, not magnetism. b) You cut a length of wire, connect the light bulb to the two ends of the wire, and pass the magnet through the loop that is formed. c) You cut two lengths of wire and connect the magnet and the bulb in series.

Short answer

Answer: Connect the bulb to a loop of wire and pass the bar magnet through the loop. This creates a changing magnetic field which generates an electric current through electromagnetic induction, lighting up the bulb.

Step-by-step solution

Understand the options

Read the provided options (a), (b) and (c) carefully and determine which one can create an electric current necessary to light the bulb through electromagnetic induction.

Analyze option (a)

Option (a) states that the bulb can't light up because the bulb needs electricity and not magnetism. This option seems to disregard the possibility of creating an electric current through a changing magnetic field, so it is not the correct answer.

Analyze option (b)

Option (b) explains that a length of wire is cut, the bulb is connected to the ends of the wire, and a loop is formed. Then the magnet is passed through the loop. Due to electromagnetic induction, the changing magnetic field inside the loop can generate an electric current that can light up the bulb. This option seems plausible.

Analyze option (c)

Option (c) suggests cutting two lengths of wire and connecting the magnet and bulb in series. However, this option does not explain how the changing magnetic field can generate an electric current, so it is not the correct answer.

Choose the correct answer

Based on the analysis of the options, option (b) is the correct answer, as it demonstrates a way to light up the bulb using the principle of electromagnetic induction.