Making a Black Light  

 

By using different types of phosphor materials to coat the fluorescent tubes, the tubes can be engineered to emit light in a wide range of colors and energies from the near-UV to the orange-red. So-called black lights emit in the violet and near-UV regions with an energy of approximately 3.5 eV.

 

Common fluorescent lamps, black lights, grow lights, and tanning lights all have the same mercury gas inside them. As a result, the excited mercury atoms emit light energy of 4.8 eV.

 

Use the Fluorescence Spectroscopy computer program and the values of 4.8 eV for the input spectrum and 3.5 eV for the output spectrum to construct an energy band model for the black light. Describe your results and include answers to: • How is the energy diagram for the black light similar to the energy diagram for the “cool white” fluorescent lamp?

 

How are they different?