RAS question
The Gupta-era Iron Pillar at Delhi demonstrates that ancient Indians had mastered:
Correct answer: (D) Rust-resistant iron metallurgy.
The Gupta-era Iron Pillar at Delhi demonstrates ancient Indian mastery of rust-resistant iron metallurgy.
Explanation
The Delhi Iron Pillar is best read as evidence of advanced iron metallurgy, not as a general craft object. Britannica describes it as a Gupta-period, six-ton iron pillar, about 7.2 metres tall, that has remained relatively rust-free for more than 1,600 years. Its composition includes 0.25 percent phosphorus, which is linked to a protective iron-hydrogen-phosphate passive film, also called misawite. Britannica similarly notes that phosphate reactions create a thin rust-protective iron hydrogen phosphate hydrate coating on the surface. The pillar's historical significance lies in corrosion-resistant iron technology, supported by controlled material choice and ironworking skill.
Why the other options are wrong
- (A) Glass making is not indicated by an iron pillar; the evidence is the pillar's iron composition and its resistance to corrosion.
- (B) Gold smelting is unrelated because the object is made largely of iron and the point turns on phosphorus-rich iron metallurgy.
- (C) Paper production has no connection with the pillar's material, construction, or rust-resistant surface chemistry.
Concept
This tests technological achievement in ancient Indian history, especially metallurgy under the Gupta-period cultural and scientific context. It recurs in RAS because material evidence such as the Iron Pillar links archaeology, science and polity in one factual example.