In MBF lamp operation, what is the purpose of the discharge process?

• A. Enables mercury vaporization and light output
• B. Heats the filament
• C. Creates barrier for safety
• D. Allows current to bypass the ballast

Answer: (A)

The discharge process creates a conducting plasma inside the lamp, which allows current to flow and ionizes the mercury vapor. This plasma formation enables the mercury to vaporize and emit UV light. Those UV photons then excite the phosphor coating, producing visible light. The ballast is what supplies and limits the current to keep the discharge going safely. The other options don’t fit because MBF fluorescent lamps don’t rely on filament heating for light in this context, the discharge isn’t about a safety barrier, and the current must pass through the ballast to sustain the arc.