How does phosphorescence differ from fluorescence?

How does phosphorescence differ from fluorescence?

• A. Phosphorescence glows only while illuminated.
• B. Fluorescence stores energy for later release.
• C. Phosphorescence stores energy and glows after exposure.
• D. Fluorescence and phosphorescence are the same.

Answer: (C)

The key idea is how long a material keeps glowing after the exciting light is removed, which depends on how electrons return to their stable state. In fluorescence, electrons absorb energy and jump to a higher energy level, but they return to the ground state almost instantly, emitting light only while the material is being illuminated. Once the light is off, the glow stops quickly. In phosphorescence, some electrons get trapped in a longer-lived, metastable state and release energy more slowly, so the material continues to glow after exposure ends. This stored energy and delayed emission are what create the afterglow, so the correct statement describes phosphorescence as storing energy and glowing after exposure.

The key idea is how long a material keeps glowing after the exciting light is removed, which depends on how electrons return to their stable state. In fluorescence, electrons absorb energy and jump to a higher energy level, but they return to the ground state almost instantly, emitting light only while the material is being illuminated. Once the light is off, the glow stops quickly. In phosphorescence, some electrons get trapped in a longer-lived, metastable state and release energy more slowly, so the material continues to glow after exposure ends. This stored energy and delayed emission are what create the afterglow, so the correct statement describes phosphorescence as storing energy and glowing after exposure.