In a fluorescent lamp, what is the typical energy conversion sequence?

In a fluorescent lamp, what is the typical energy conversion sequence?

• A. Electrical energy → Mercury vapor → Ultraviolet light → Phosphor particles → Visible light energy
• B. Electrical energy → Thermal energy → Visible light energy
• C. Electrical energy → Chemical energy → Visible light energy
• D. Electrical energy → Radio waves → Visible light energy

Answer: (A)

The main idea here is how a fluorescent lamp converts electrical energy into visible light through two stage light production: first ultraviolet light is generated, then that UV light is converted into visible light by the phosphor coating. Electrical energy powers a discharge in the mercury vapor inside the lamp, producing ultraviolet photons. That ultraviolet light then strikes a phosphor coating on the inside of the tube, and the phosphor absorbs the UV energy and re-emits it as visible light. So the typical energy path is electrical energy → mercury vapor → ultraviolet light → phosphor → visible light energy. Some energy is inevitably lost as heat along the way, but the defining sequence is the UV production followed by phosphor fluorescence to give visible light.

The main idea here is how a fluorescent lamp converts electrical energy into visible light through two stage light production: first ultraviolet light is generated, then that UV light is converted into visible light by the phosphor coating.

Electrical energy powers a discharge in the mercury vapor inside the lamp, producing ultraviolet photons. That ultraviolet light then strikes a phosphor coating on the inside of the tube, and the phosphor absorbs the UV energy and re-emits it as visible light. So the typical energy path is electrical energy → mercury vapor → ultraviolet light → phosphor → visible light energy. Some energy is inevitably lost as heat along the way, but the defining sequence is the UV production followed by phosphor fluorescence to give visible light.