RAS question
The Gupta period Iron Pillar at Mehrauli (Delhi) is an outstanding example of metallurgical skill because:
Correct answer: (B) It has not rusted despite being over 1,500 years old.
The Gupta-period Iron Pillar at Mehrauli is an outstanding example of metallurgical skill because it has resisted rust and corrosion for more than 1,500 years.
Explanation
The point of the question is corrosion resistance, not size or ornament. The pillar is attributed to Chandragupta II and is linked with a 4th-century Sanskrit inscription naming Chandra, believed to be the Gupta king Chandragupta II. Its survival is attributed to high phosphorus content forming a protective passive layer. The UNESCO advisory evaluation calls the rust-free iron pillar testimony to ancient Indian metallurgical skill and describes its remarkable lack of corrosion. It also notes that the pillar is made of many small wrought-iron blooms welded together and that the absence of corrosion is connected with factors such as wrought iron's resistance and Delhi's climatic conditions.
Why the other options are wrong
- (A) The UNESCO evaluation describes the pillar as 7.02 m long, so the claim that it is valued because it was the tallest iron structure in the ancient world is not the stated reason.
- (C) The pillar is described as many small wrought-iron blooms welded together, not modern welding techniques, and the MCQ asks about Gupta-period metallurgical skill.
- (D) The corrosion discussion concerns wrought iron, not any gold-alloy coating.
Concept
This tests Gupta-period science and technology, especially ancient Indian metallurgy. RAS asks such questions because monuments often link political history with material culture and technological achievement.