Q. 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

61. निम्नलिखित कथनों पर विचार कीजिए:

कथन I:
कुछ दुर्लभ मृदा तत्त्व, सपाट टेलीविजन स्क्रीन और कम्प्यूटर मॉनीटर के निर्माण में प्रयुक्त होते हैं।

कथन II :
कुछ दुर्लभ मृदा तत्वों में स्फुरदीप्त गुणधर्म होते हैं।

उपर्युक्त कथनों के संदर्भ में, निम्नलिखित में से कौन-सा एक सही है?

(a) कथन I और कथन II दोनों सही है तथा कथन II, कथन I की व्याख्या करता है
(b) कथन I और कथन II दोनों सही हैं किन्तु कथन II, कथन I की व्याख्या नहीं करता है
(c) कथन I सही है किन्तु कथन II सही नहीं है
(d) कथन I सही नहीं है किन्तु कथन II सही है

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

Explanation:

• Statement I is correct: Rare earth elements like europium, terbium, and yttrium are used in manufacturing phosphors, essential components of LED, LCD, and CRT displays used in flat-screen TVs and monitors.
• Statement II is correct: Rare earth elements such as europium, terbium, and cerium exhibit phosphorescence and luminescence, meaning they can absorb energy and re-emit it as light, a property critical for display technologies.
• Statement II explains why rare earths are used in display technologies, their phosphorescent property is what makes them suitable for creating vibrant colors in TV/computer screens.

Source: https://www.irel.co.in/faq