What device in older cars uses electromagnetic induction to increase voltage?

The correct answer is the coil, which in older cars serves a critical function in the ignition system. The coil, or ignition coil, is designed to transform the low voltage from the battery into a much higher voltage. It utilizes electromagnetic induction, which is the process by which a changing magnetic field can generate an electric current.

Here's how it works: the ignition coil consists of two wire coils, known as the primary and secondary coils. When the ignition key is turned on, current flows through the primary coil, creating a magnetic field. When the electrical circuit is interrupted by the ignition points opening, the magnetic field collapses rapidly. This rapid change generates a high voltage in the secondary coil, often exceeding 40,000 volts, which is necessary to create a spark at the spark plugs for engine ignition.

In contrast, the distributor is responsible for timing and directing the high voltage from the coil to the correct cylinder at the right moment. The starter motor, on the other hand, is responsible for turning the engine over to start it, relying on battery voltage. A generator converts mechanical energy to electrical energy but does not primarily focus on transforming battery voltage for ignition purposes. Therefore, the coil's role in using electromagnetic induction to boost the voltage is what makes it