Question

What makes a "fluorescent" highlighter marker so bright?

Answer 1

Fluorescent highlighter ink is unusually bright because it converts some of the incident ultraviolet light that is invisible to humans into visible light.

Answer 2

Answer:

=> Fluorescent highlighter ink is unusually bright because it converts some of the incident ultraviolet light that is invisible to humans into visible light.

For example, take a normal yellow marker and a yellow highlighter marker which contains a yellow fluorescent chemical mixed into the ink.

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