60 practice questions on Nanotechnology & Materials from the Science & Technology section of the UPSC Prelims syllabus.
60 come with a written explanation and 12 are actual previous year questions.
Try the sample set below - the answer stays hidden until you ask for it.
5 Easy35 Medium20 Hard12 from past papers
Sample questions
Q1
Previous year questionmedium
Organic Light Emitting Diodes (OLEDs) are used to create digital display in many devices. What are the advantages of OLED displays over Liquid Crystal displays?
1. OLED displays can be fabricated on flexible plastic substrates.
2. Roll-up displays embedded in clothing can be made using OLEDs.
3. Transparent displays are possible using OLEDs.
Select the correct answer using the code given below :
A1 and 3 only
B2 only
C1, 2 and 3
DNone of the above statements is correct
Show answer and explanation
Correct answer: C - 1, 2 and 3
OLEDs are self-emissive organic films that need no backlight, which gives all three advantages. They can be deposited on thin flexible plastic substrates (1), enabling roll-up or wearable displays embedded in fabric (2), and they can be made transparent because the emissive layers and electrodes can be largely see-through (3). LCDs, by contrast, require rigid glass and a bulky backlight, so they cannot match these properties. Hence 1, 2 and 3 are all correct.
Q2
Previous year questionmedium
Consider the following statements:
1. Other than those made by humans, nanoparticles do not exist in nature.
2. Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics.
3. Nanoparticles of some commercial products which enter the environment are unsafe for humans.
Which of the statements given above is/are correct?
A1 only
B3 only
C1 and 2
D2 and 3
Show answer and explanation
Correct answer: D - 2 and 3
Nanoparticles occur naturally too, for example in volcanic ash and sea spray, so the claim that they exist only when human-made makes statement 1 wrong. Metallic oxide nanoparticles such as titanium dioxide and zinc oxide are used in cosmetics and sunscreens, so statement 2 is correct. Certain commercial nanoparticles released into the environment can be harmful to human health, so statement 3 is correct. Hence only 2 and 3 are correct.
Q3
Previous year questionmedium
Consider the following statements :
Statement I : Some rare earth elements are used in the manufacture of flat television screens and computer monitors.
Statement II : Some rare earth elements have phosphorescent properties.
Which one of the following is correct in respect of the above statements?
ABoth Statement I and Statement II are correct and Statement II explains Statement I
BBoth Statement I and Statement II are correct but Statement II does not explain Statement I
CStatement I is correct but Statement II is not correct
DStatement I is not correct but Statement II is correct
Show answer and explanation
Correct answer: A - Both Statement I and Statement II are correct and Statement II explains Statement I
Rare earth elements such as europium, terbium and yttrium are used in flat television screens and computer monitors, so statement I is correct, and these elements indeed possess phosphorescent or luminescent properties, so statement II is correct. It is precisely because of their phosphorescent behaviour that they are used to produce colours in display screens, so statement II explains statement I. Hence both are correct and II explains I.
Q4
Previous year questionmedium
Graphene is frequently in news recently. What is its importance?
1. It is a two-dimensional material and has good electrical conductivity.
2. It is one of the thinnest but strongest materials tested so far.
3. It is entirely made of silicon and has high optical transparency.
4. It can be used as 'conducting electrodes' required for touch screens, LCDs and organic LEDs.
Which of the statements given above are correct?
A1 and 2 only
B3 and 4 only
C1, 2 and 4 only
D1, 2, 3 and 4
Show answer and explanation
Correct answer: C - 1, 2 and 4 only
Statements 1, 2 and 4 are correct. Graphene is a single two-dimensional sheet of carbon atoms in a honeycomb lattice with excellent electrical conductivity, and it is among the thinnest and strongest materials ever tested. Because it is conductive, transparent and flexible, it is a candidate for transparent conducting electrodes in touch screens, liquid crystal displays and organic LEDs. Statement 3 is wrong on a basic fact: graphene is made entirely of carbon, not silicon, even though it does have high optical transparency. Any option including statement 3 is therefore eliminated, giving (c).
Q5
Previous year questionmedium
Recently, there has been a concern over the short supply of a group of elements called 'rare earth metals'. Why?
1. China, which is the largest producer of these elements, has imposed some restrictions on their export.
2. Other than China, Australia, Canada and Chile, these elements are not found in any country.
3. Rare earth metals are essential for the manufacture of various kinds of electronic items and there is a growing demand for these elements.
Which of the statements given above is/are correct?
A1 only
B2 and 3 only
C1 and 3 only
D1, 2 and 3
Show answer and explanation
Correct answer: C - 1 and 3 only
Rare earth metals are vital for electronics, magnets, batteries and many high-tech goods whose demand is rising, and China, the dominant producer, had restricted exports, so statements 1 and 3 are correct. Rare earths are actually found in several other countries including the USA and India, so statement 2 (claiming they occur only in China, Australia, Canada and Chile) is wrong. The answer is 1 and 3 only.
Q6
Previous year questionhard
With reference to carbon nanotubes, consider the following statements:
1. They can be used as carriers of drugs and antigens in the human body.
2. They can be made into artificial blood capillaries for an injured part of human body.
3. They can be used in biochemical sensors.
4. Carbon nanotubes are biodegradable.
Which of the statements given above are correct?
A1 and 2 only
B2, 3 and 4 only
C1, 3 and 4 only
D1, 2, 3 and 4
Show answer and explanation
Correct answer: C - 1, 3 and 4 only
Carbon nanotubes can carry drugs and antigens into the body (statement 1) and are used in biochemical sensors owing to their large surface area and electrical conductivity (statement 3), and research shows they can be broken down by certain oxidative enzymes, so they are taken as biodegradable (statement 4). Statement 2 is not accepted in the official UPSC key: building functional artificial blood capillaries from carbon nanotubes is not an established application. Hence the correct combination is 1, 3 and 4 only.
Q7
Previous year questionmedium
There is some concern regarding the nanoparticles of some chemical elements that are used by the industry in the manufacture of various products. Why?
1. They can accumulate in the environment, and contaminate water and soil. 2. They can enter the food chains. 3. They can trigger the production of free radicals. Select the correct answer using the code given below.
A1 and 2 only
B3 only
C1 and 3 only
D1, 2 and 3
Show answer and explanation
Correct answer: D - 1, 2 and 3
All three concerns are valid. Engineered nanoparticles can persist and accumulate in the environment, contaminating water and soil; their tiny size lets them enter and move up food chains; and they can trigger the production of reactive oxygen species (free radicals) that damage living cells. Since statements 1, 2 and 3 are all correct, the answer is 1, 2 and 3.
Q8
Previous year questionmedium
Consider the following statements:
1. Carbon fibres are used in the manufacture of components used in automobiles and aircraft.
2. Carbon fibres once used cannot be recycled.
Which of the statements given above is/are correct?
A1 only
B2 only
CBoth 1 and 2
DNeither 1 nor 2
Show answer and explanation
Correct answer: A - 1 only
Statement 1 is correct: carbon fibres, prized for their high strength-to-weight ratio and stiffness, are widely used in components for automobiles, aircraft, sports goods and wind turbine blades. Statement 2 is incorrect: carbon fibres and carbon-fibre-reinforced composites can be recycled - for instance through pyrolysis or solvolysis that recover the fibres from the resin matrix for reuse - so the claim that they cannot be recycled is false. Only statement 1 holds, giving option (a). Options (b), (c) and (d) wrongly accept the false recycling claim or reject the true first statement.
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