UPSC CSE Prelims
Question 26
What is the role of ultraviolet (UV) radiation in the water purification systems?
- It inactivates/kills the harmful microorganisms in water.
- It removes all the undesirable odours from the water.
- It quickens the sedimentation of solid particles, removes turbidity and improves the clarity of water.
Which of the statements given above is/are correct?
View correct answer and explanation
Correct answer: A
Correct Option: A
Explanation: UV water purification inactivates microbial DNA/RNA; it does not mechanically remove dissolved odours or settle suspended solids.
Statement/Item-wise Analysis:
1: Correct - Germicidal UV damages microorganisms and prevents reproduction.
2: Incorrect - Odour removal typically requires adsorption or other treatment, not UV alone.
3: Incorrect - Clarification and turbidity reduction require filtration/coagulation/sedimentation, not UV irradiation.
Option-wise Analysis:
A: Correct - includes exactly the valid statements/items and excludes the invalid ones.
B: Incorrect - includes incorrect items 2, 3; omits correct item 1.
C: Incorrect - includes incorrect item 3.
D: Incorrect - includes incorrect items 2, 3.