Which of the following is referred to as Electromagnetic Interference (EMI)?

EMI refers to electrical line noise generated by electromagnetic radiation from external sources (motors, fluorescent lights, radio signals) that induces unwanted current on cables or power lines. It is distinguished from power anomalies by its origin in radiated or conducted electromagnetic energy rather than supply-side voltage changes.

A spike is a very brief, high-magnitude overvoltage event on the power line, classified as a power quality anomaly rather than EMI.

A transient is a short-duration voltage disturbance (overvoltage or undervoltage) on the power supply, not an electromagnetic interference phenomenon.

A brownout is a sustained, intentional or unintentional reduction in supply voltage, which is a power delivery issue unrelated to electromagnetic interference.