🧷 Authentic Classroom Explanation by IAS Monk

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📌 The Question:

Consider the following statements:

Statement I: Some rare earth elements are used in the manufacture of flat television screens and computer monitors.
Statement II: Some rare earth elements have phosphorescent properties.

Which one of the following is correct in respect of the above statements?

(a) Both Statement I and Statement II are correct and Statement II explains Statement I
(b) Both Statement I and Statement II are correct but Statement II does not explain Statement I
(c) Statement I is correct but Statement II is not correct
(d) Statement I is not correct but Statement II is correct

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✅ Answer:

(a) Both Statement I and Statement II are correct and Statement II explains Statement I

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🧑‍🏫 Authentic Classroom Explanation:

🔹 Statement I — Correct ✅

Rare earth elements (REEs) such as europium, terbium, and yttrium are extensively used in flat-panel televisions, LED displays, and computer monitors.
They are critical in producing red, green, and blue (RGB) colours in modern display technologies.

🔹 Statement II — Correct and Explanatory ✅

Several rare earth elements possess phosphorescent / luminescent properties, meaning they emit visible light when excited by electrons or photons.
This property is directly responsible for their use in screens, where controlled light emission is required for sharp, bright, and colour-accurate displays.

📌 Therefore, Statement II correctly explains Statement I.

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🔍 Curiosity Raiser:

Why does China dominate the rare-earth supply chain despite not having the largest reserves? 🤔
Because processing expertise, not mere availability, controls technological power.

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🧠 Enrichment Notes (Prelims Value-Add):

• Key REEs for Displays:
  • Europium → Red phosphor
  • Terbium → Green phosphor
  • Yttrium → Host lattice for phosphors
• REEs are strategic minerals used in:
  • Smartphones & screens
  • Wind turbines
  • EV motors
  • Missile guidance systems
• UPSC frequently links REEs with geopolitics & technology dependence

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🪔 IAS Monk Whisper:

“In the modern world, colours on a screen often reflect power beneath the ground.”