✅ Answer: A) 1 and 2 onlyStatements 1 and 2 are correct. Graphene is a single layer of carbon atoms arranged in a hexagonal lattice. It is about 200 times stronger than steel. Statement 3 is incorrect — graphene was discovered/isolated in 2004 by Andre Geim and Konstantin Novoselov (not 2010). The Nobel Prize in Physics was awarded in 2010 for the discovery. Graphene also conducts electricity better than copper and is nearly transparent.

✅ Answer: C) Quantum dotsThe Nobel Prize in Chemistry 2023 was awarded to Moungi Bawendi, Louis Brus, and Alexei Ekimov for the discovery and synthesis of quantum dots. Quantum dots are semiconductor nanocrystals (2-10 nm) that emit different colours depending on their size. They are used in QLED TV displays, solar cells, medical imaging, and biosensors. The Nobel Prize for Fullerenes was in 1996; for Graphene in Physics 2010; for CRISPR in Chemistry 2020.

✅ Answer: A) Antimicrobial properties that kill bacteria and virusesNano-silver (silver nanoparticles) is used in water purification because it has strong antimicrobial properties — it kills bacteria, viruses, and fungi. Silver ions released from nanoparticles disrupt microbial cell membranes and DNA. Nano-silver is also used in wound dressings, medical devices, textiles, and food packaging. India’s CSIR labs have developed affordable nano-silver water purification systems for rural areas. However, concerns exist about nano-silver’s environmental impact.

✅ Answer: A) Can image and manipulate individual atoms on surfacesThe Scanning Tunnelling Microscope (STM) can image and manipulate individual atoms on surfaces. It was invented by Gerd Binnig and Heinrich Rohrer in 1981 (Nobel Prize in Physics 1986). STM uses quantum tunnelling — electrons tunnel through the gap between the tip and surface. It can achieve atomic resolution. In 1989, IBM scientists used STM to spell “IBM” using 35 xenon atoms — the first demonstration of atomic manipulation. STM is a fundamental tool for nanotechnology research.

✅ Answer: A) Return to their original shape when heated after being deformedShape Memory Alloys (SMAs) return to their original shape when heated after being deformed. The most common SMA is Nitinol (Nickel-Titanium alloy). Applications: medical stents (expand in body heat), orthodontic wires, actuators, aerospace components, and robotics. SMAs are a type of “smart material.” Other smart materials: piezoelectric materials (generate electricity when stressed), magnetostrictive materials (change shape in magnetic fields), and electrochromic materials (change colour with voltage).

✅ Answer: A) Release nutrients slowly and precisely, reducing waste and environmental pollutionNano-enabled fertilizers (nano-fertilizers) release nutrients slowly and precisely to plant roots, reducing waste and environmental pollution. Conventional fertilizers release nutrients rapidly — much is lost through leaching, runoff, and volatilisation. Nano-fertilizers can increase nutrient use efficiency by 30-50%. They reduce groundwater contamination and greenhouse gas emissions. India’s ICAR and CSIR are developing nano-fertilizers. Nano-urea (developed by IFFCO) is India’s first nano-fertilizer approved for commercial use.

✅ Answer: C) Fullerenes (C₆₀)The Nobel Prize in Chemistry 1996 was awarded to Robert Curl, Harold Kroto, and Richard Smalley for the discovery of fullerenes (C₆₀). They discovered fullerenes in 1985 while studying carbon in space. C₆₀ was named “Buckminsterfullerene” after architect Buckminster Fuller. Fullerenes are spherical carbon cages resembling a soccer ball. They are also called “Buckyballs.” Applications: drug delivery, lubricants, superconductors, and solar cells.

✅ Answer: A) Is India’s first nano-fertilizer that can replace conventional ureaIFFCO’s Nano Urea is India’s first nano-fertilizer, developed by IFFCO (Indian Farmers Fertiliser Cooperative). It was approved for commercial use in 2021. A 500 ml bottle of Nano Urea can replace one 45 kg bag of conventional urea. It is applied as a foliar spray (on leaves) rather than soil application. It increases nutrient use efficiency, reduces soil and water pollution, and lowers import dependence on urea. India imports significant amounts of urea — Nano Urea can reduce this dependence.

✅ Answer: A) Drug delivery — encapsulating drugs in lipid vesicles for targeted deliveryLiposomes are nano-sized lipid vesicles (spherical structures made of lipid bilayers) used to encapsulate drugs for targeted delivery. They protect drugs from degradation, improve drug solubility, and can be engineered to target specific cells. Liposomal doxorubicin (Doxil) is an approved cancer drug. mRNA vaccines (Pfizer-BioNTech, Moderna) use lipid nanoparticles (similar to liposomes) to deliver mRNA. Liposomes are also used in cosmetics and gene therapy.

✅ Answer: B) Norio TaniguchiThe term “nanotechnology” was coined by Norio Taniguchi, a Japanese scientist, in 1974. He used it to describe precision machining at the nanometre level. Richard Feynman’s 1959 lecture “There’s Plenty of Room at the Bottom” is considered the conceptual birth of nanotechnology (he is called the “Father of Nanotechnology”). Eric Drexler popularised nanotechnology with his 1986 book “Engines of Creation.” Andre Geim discovered graphene (Nobel Prize 2010).