GED Science Practice

What is "Phosphorescence"?

1. a) Colorless watery fluid of blood and lymph

2. b) A stable particle in the bloodstream

3. c) Aggregate of small plant and animal organisms

4. d) A fluorescence that persists after radiation

The correct answer is: d) A fluorescence that persists after radiation

Phosphorescence is the phenomenon where a substance absorbs light or other forms of radiation and then re-emits that energy over an extended period, even after the source of excitation is removed. This process is distinct from immediate fluorescence, which occurs only when the radiation source is present. The correct option describes this persistent emission of light, which is characteristic of phosphorescent materials. These materials can continue to glow in the dark after being exposed to a light source, making this answer accurate. The other options do not relate to the concept of phosphorescence. The first option refers to the plasma component of blood, the second discusses stable particles (such as cells or cell fragments) in the bloodstream, and the third relates to small organisms in an ecological context. None of these choices describe a process involving light emission or persistence, which is central to understanding phosphorescence.