What does electromagnetic interference (EMI) refer to?

Electromagnetic interference (EMI) refers specifically to disruptions that occur when electrical noise from electric or magnetic fields affects electronic devices or systems. This phenomenon can arise from a variety of sources, such as electrical equipment, radio transmissions, and even natural sources like lightning. The key aspect of EMI is that it pertains to the unwanted effects caused by electromagnetic fields generated by electronic components, which can lead to degradation in performance or can even cause devices to malfunction.

In this context, the other options do not accurately capture the essence of EMI. For example, while noise from mechanical systems or communication equipment may interfere with performance, they do not specifically relate to the electromagnetic nature of the disturbances. Similarly, static electricity in data lines, while a form of electrical noise, does not encompass the broader concept of EMI, which includes the effects of both electric and magnetic fields on electronic systems. Thus, the definition tied to electrical noise from electric or magnetic fields is the most accurate representation of electromagnetic interference.