UPSC CSE Prelims
Question 31
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?
View correct answer and explanation
Correct answer: A
Correct Option: A (Both Statement I and Statement II are correct and Statement II explains Statement I)
Explanation: Rare-earth elements such as europium and terbium are used in display phosphors because they can emit characteristic light after excitation. Thus their luminescent properties explain their use in televisions and monitors.
Statement / Pair / Item-wise Analysis:
I: True-rare-earth phosphors supply red and green screen colours.
II: True-luminescent/phosphor properties enable the display application and explain I.
Option-wise Analysis:
A. Correct-this matches the facts and the item-wise assessment above.
B. Incorrect-this does not reflect the actual truth values or explanation relationship of the statements.
C. Incorrect-this contradicts the specific facts evaluated in the analysis above.
D. Incorrect-this contradicts the specific facts evaluated in the analysis above.