UPSC CSE Prelims
Question 37
Magnetite particles, suspected to cause neurodegenerative problems, are generated as environmental pollutants from which of the following?
- Brakes of motor vehicles
- Engines of motor vehicles
- Microwave stoves within homes
- Power plants
- Telephone lines
Select the correct answer using the code given below.
View correct answer and explanation
Correct answer: B
Correct Option: B (1, 2 and 4 only)
Explanation: Fine magnetite particles can form from vehicle brake wear, engine exhaust and coal/industrial power-plant emissions; microwave ovens and telephone lines are not comparable combustion/wear sources.
Statement / Pair / Item-wise Analysis:
1. Correct / qualifies - Frictional brake wear can shed iron-oxide magnetic nanoparticles.
2. Correct / qualifies - Vehicle engines/exhaust may emit iron-rich magnetite particles.
3. Incorrect / does not qualify - Domestic microwave ovens are not the typical environmental generation source identified.
4. Correct / qualifies - Power-plant combustion and ash can release magnetic particles.
5. Incorrect / does not qualify - Telephone lines do not generate such particulate pollution.
Option-wise Analysis:
A. Incorrect-includes item 3, which is not valid (Domestic microwave ovens are not the typical environmental generation source identified); includes item 5, which is not valid (Telephone lines do not generate such particulate pollution); omits valid item 4 (Power-plant combustion and ash can release magnetic particles).
B. Correct-selects exactly the supported statements/items: 1, 2, 4.
C. Incorrect-includes item 3, which is not valid (Domestic microwave ovens are not the typical environmental generation source identified); includes item 5, which is not valid (Telephone lines do not generate such particulate pollution); omits valid item 1 (Frictional brake wear can shed iron-oxide magnetic nanoparticles); omits valid item 2 (Vehicle engines/exhaust may emit iron-rich magnetite particles).
D. Incorrect-includes item 3, which is not valid (Domestic microwave ovens are not the typical environmental generation source identified); includes item 5, which is not valid (Telephone lines do not generate such particulate pollution).