Nanotechnology and New Materials — Practice Questions
UPSC Prelims-pattern practice questions on nanotechnology with explanations — nanoscale, Nitinol, piezoelectrics, aerogels and superconductors.
Questions
These are original UPSC-pattern practice questions. Attempt each one before revealing the answer.
One nanometre is equal to
Solution
1 nm = one-billionth of a metre (10⁻⁹ m). One-thousandth of a metre is a millimetre, one-millionth is a micrometre, and one-trillionth is a picometre.
Answer: C
Nitinol, a shape-memory alloy used in medical stents and orthodontic wires, is composed mainly of
Solution
Nitinol is a nickel–titanium alloy (the name comes from Nickel Titanium Naval Ordnance Laboratory). It returns to its original shape when heated. The other options are distractors built on the letters of the name.
Answer: B
Consider the following:
- A quartz crystal in a gas lighter producing a spark when pressed.
- Spectacle lenses that darken in sunlight.
- A bimetallic strip in a thermostat bending on heating.
Which of the above is/are based on the piezoelectric effect?
Solution
Only item 1 — squeezing a quartz crystal produces a voltage large enough to spark. Item 2 is photochromism (a chemical response to ultraviolet light). Item 3 is unequal thermal expansion of two metals.
Answer: A
Consider the following statements about aerogels:
- They have extremely low density.
- They are excellent thermal insulators.
- They are made by replacing the liquid in a gel with a gas without collapsing its structure.
Which of the statements given above is/are correct?
Solution
All three are correct. The liquid in a gel is removed (typically by supercritical drying) and replaced with gas while the solid network survives. The product is mostly air — extremely light and an excellent insulator.
Answer: D
Consider the following statements about superconductors:
- They show zero electrical resistance below a critical temperature.
- They expel magnetic fields from their interior, a phenomenon called the Meissner effect.
- They are used in the magnets of MRI scanners.
- Superconductors that work at room temperature and normal pressure are in wide commercial use.
How many of the statements given above are correct?
Solution
Statements 1, 2 and 3 are correct. Statement 4 is incorrect — no room-temperature, ambient-pressure superconductor has been confirmed; the LK-99 claim (2023) failed independent replication. Three are correct.
Answer: C
What are nano-fertilisers? Discuss their potential benefits for Indian agriculture and the questions that must be answered before their large-scale adoption.
Solution
Introduction: Nano-fertilisers supply nutrients as nanoscale particles, usually as a foliar spray, aiming for higher absorption by plants. IFFCO introduced liquid Nano Urea in 2021 and Nano DAP in 2023.
Body:
- Potential benefits: higher nutrient-use efficiency because of the large surface area of nanoparticles; lower quantities of conventional fertiliser; reduced run-off and nitrate pollution of water; lower logistics and storage costs (small bottles instead of bags); lower subsidy burden if they genuinely substitute bulk fertiliser.
- Questions to answer: consistency of yield results across crops, soils and seasons (agronomic studies have reported mixed outcomes); the right dose and timing; long-term effects on soil microbes and human health; whether foliar sprays can meet a crop’s total nitrogen needs.
- Regulatory and extension aspects: the 2020 guidelines for nano-based agri-inputs; need for independent, multi-location trials; farmer training and transparent data.
Conclusion: Nano-fertilisers could make farming more efficient and less polluting, but promotion should follow robust, independent field evidence to protect both farm incomes and soil health.