Glowing in the Dark

question 172

Multiple Choice

Glowing in the Dark
Have you ever wondered how glow-in-the-dark things actually glow in the dark? Most glow-in-the-dark items glow because of something called phosphorescence or photoluminescence. Phosphorescent items must be "charged" under a bright light before they actually glow in the dark. This charging process works because of a substance called phosphor.
When light from the sun or a lamp hits phosphor, the phosphor molecules absorb the light and become energized. As the phosphor molecules release the stored energy, they emit a dim light that is visible in the dark. The color of the light that they produce depends on the color of the dye added to the glow-in-the-dark item. Usually, green dye is added to the phosphors to make the light easier to see. Although any color can be used, the human eye sees green light most clearly in the dark.
There are also a few glow-in-the-dark items that do not need to be charged. Emergency exit signs, gun sights, and certain kinds of expensive wristwatches glow because of radioluminescence. In these items, the phosphor is mixed with a radioactive element called tritium. The radiation from the tritium provides energy to the phosphor. It is almost as if there are thousands of tiny lamps constantly shining on the phosphor. Because their phosphor is always energized, these radioluminescent items are always glowing.
One other kind of glow-in-the-dark item that does not require charging is the glow stick. Glow sticks do not need to be held under light and do not contain any radioactive elements. Instead, glow sticks glow using chemiluminescence. Glow sticks contain a fluorescent dye and a thin glass tube that contains a chemical. To activate a glow stick, you bend the plastic container, causing the glass to break. The chemical inside the glass then mixes with the dye. The combination of the chemical and the dye produces visible light.
Question: Why does the author mention "thousands of tiny lamps" in paragraph three?

• A)To link two different elements that are found in nature.
• B)To suggest that the radiation from tritium acts as if it were a lamp.
• C)To state that the light emitted from the phosphor is as bright as a lamp.
• D)To explain that a lamp must shine on tritium in order for it to glow.

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Definitions:

Reciprocal Interdependence

A relationship between two or more elements in a system where each influences or is influenced by the other, creating a mutual dependency.

Team Coaching

The practice of providing guidance, strategies, and feedback to teams with the aim of enhancing their performance, cohesion, and effectiveness.

Coaching Interventions

are structured forms of guidance provided by a coach aiming to improve the performance or development of individuals or teams.

High-learning Orientation

Refers to an individual's or organization's proactive stance towards learning, emphasizing continuous improvement and adaptability.