by Q. Consider the following statements:
UPSC Civil Services Examination (Prelims) 2025 – General Studies Paper I
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
Answer: (a) Both Statement I and Statement II are correct and Statement II explains Statement I
Explanation:
Statement I is correct.
Several rare earth elements (REEs) are used in the manufacture of flat television screens and computer monitors. Elements such as europium, terbium, and yttrium are commonly used in display technologies to produce bright and precise colours, especially in LED, LCD, and older plasma display systems.
Statement II is correct.
Some rare earth elements possess phosphorescent (and fluorescent) properties, meaning they can emit visible light when excited by energy, such as electrons or ultraviolet radiation.
Link between the statements:
The phosphorescent properties of rare earth elements are exactly why they are used in TV and computer display screens to generate red, green, and blue colours with high efficiency and clarity.
Answer: (a) Both Statement I and Statement II are correct and Statement II explains Statement I
