Which of the following is a part of a spark plug assembly?

The ground electrode is an essential component of a spark plug assembly, playing a crucial role in igniting the air-fuel mixture in an internal combustion engine. When the ignition system generates a high-voltage electrical spark, this spark travels from the center electrode to the ground electrode, creating a gap where the spark can ignite the mixture. The ground electrode is typically positioned at the end of the spark plug, extending into the combustion chamber, and it works with the center electrode to ensure a reliable ignition process.

The other options represent components used in different systems. For instance, the governor arm is typically part of a governor mechanism that regulates engine speed, the fuel injector delivers fuel into the combustion chamber, and the condenser is associated with spark energy management in specific ignition systems rather than forming part of the spark plug assembly itself. Understanding the specific roles and relationships of these components helps clarify the function of the spark plug within an engine.