What are the two conditions that must exist for static electricity to act as an ignition source?

The correct choice identifies the two essential conditions for static electricity to serve as an ignition source. First, a spark discharge must occur, meaning that there needs to be a sudden release of accumulated electrical energy in the form of a spark. This spark can ignite flammable materials if they are present in sufficient concentrations. Second, there must be a mechanism for accumulating a static charge. This can occur through friction between materials, leading to the build-up of static electricity.

Both of these conditions are critical in understanding how static electricity can lead to ignition. Without the accumulation of charge, there would be no potential for a spark to discharge; conversely, without the discharge itself, the accumulated charge would not present an ignition risk. Static electricity poses a significant hazard in environments with flammable vapors, dust, or liquids, making awareness of these conditions crucial for safety.

The other options do not relate to the mechanisms of static electricity ignition. For instance, the presence of a strong magnetic field or radioactivity does not inherently relate to static charge build-up or discharge. Similarly, high humidity can reduce static charge build-up rather than promote it, and the operational status of electrical equipment or temperature conditions do not directly correlate with the requirements for static electricity to act as an ignition source