Statement I: Some rare earth elements are used in the manufacture of flat television screens and computer…
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?
Both Statement I and Statement II are correct and Statement II explains Statement I
Both Statement I and Statement II are correct but Statement II does not explain Statement I
Statement I is correct but Statement II is not correct
Statement I is not correct but Statement II is correct
Solution
Rare earth elements (Eu, Tb, Y, etc.) have phosphorescent properties (II), which is precisely why they are used in flat displays as phosphors (I). Statement II explains Statement I. [Sources disagree: Insights IAS — A; Prepp — B.]