Q2651. Which of the following approaches involves assembling atoms or molecules to build nanoscale structures?
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Q2652. Identify the incorrect statement regarding nanomaterials.
Explanation
Carbon nanotubes are actually exceptional conductors of electricity, far superior to wood and even better than some metals like copper. They have the ability to carry high electrical currents with very little resistance. Other statements are correct: gold nanoparticles can appear red or purple; breaking down bulk materials increases their relative surface area; and graphene is famously the thinnest known material.
Q2653. The scanning tunneling microscope (STM) and atomic force microscope (AFM) are essential tools in nanotechnology because they allow scientists to:
Explanation
Standard optical microscopes cannot see objects at the nanoscale because they are limited by the wavelength of light. The scanning tunneling microscope and atomic force microscope are revolutionary tools that use physical probes to map the surface of materials at the atomic level. These instruments not only allow scientists to visualize individual atoms but also enable them to physically move and manipulate them.
Q2654. The famous 1959 lecture "There’s Plenty of Room at the Bottom", which conceptually launched nanotechnology, was given by:
Explanation
Richard Feynman gave the 1959 lecture There’s Plenty of Room at the Bottom, which is seen as the conceptual start of nanotechnology.
Q2655. Consider the following statements regarding applications of nanotechnology in medicine (nanomedicine):
I. Nanoparticles can be engineered for targeted drug delivery to cancer cells, minimizing damage to healthy cells.
II. Magnetic nanoparticles are used as contrast agents to enhance MRI imaging.
III. Nanoshells can be injected into tumors and heated using infrared light to destroy cancer cells.
IV. Nanorobots are currently widely used in hospitals to perform complex open-heart surgeries independently.
Which of the above statement(s) is/are correct?
I. Nanoparticles can be engineered for targeted drug delivery to cancer cells, minimizing damage to healthy cells.
II. Magnetic nanoparticles are used as contrast agents to enhance MRI imaging.
III. Nanoshells can be injected into tumors and heated using infrared light to destroy cancer cells.
IV. Nanorobots are currently widely used in hospitals to perform complex open-heart surgeries independently.
Which of the above statement(s) is/are correct?
Explanation
Nanomedicine utilizes nanoparticles for targeted drug delivery to tumors and uses magnetic particles as contrast agents to improve MRI scans. Nanoshells are also used in photothermal therapy to selectively heat and kill cancer cells. However, nanorobots capable of performing independent surgeries are still largely in the theoretical stages and are certainly not yet widely used in hospitals for complex operations.
Q2656. Consider the following statements about nanotechnology applications:
I. Zinc oxide and titanium dioxide nanoparticles are used in sunscreens because they absorb UV light and are transparent on the skin.
II. Silver nanoparticles are integrated into wound dressings and fabrics for their strong antimicrobial properties.
III. Nanofilters can remove viruses and heavy metal ions from contaminated water.
IV. Quantum dots are used in modern displays (QLED TVs) for brighter and more accurate colors.
V. Nanomaterials are unable to store hydrogen for clean energy applications.
Which of the above statement(s) is/are correct?
I. Zinc oxide and titanium dioxide nanoparticles are used in sunscreens because they absorb UV light and are transparent on the skin.
II. Silver nanoparticles are integrated into wound dressings and fabrics for their strong antimicrobial properties.
III. Nanofilters can remove viruses and heavy metal ions from contaminated water.
IV. Quantum dots are used in modern displays (QLED TVs) for brighter and more accurate colors.
V. Nanomaterials are unable to store hydrogen for clean energy applications.
Which of the above statement(s) is/are correct?
Explanation
Nanotechnology has widespread applications: nanoparticles in sunscreens provide UV protection; silver nanoparticles serve as potent antimicrobials; nanofilters are used for water purification; and quantum dots enhance modern QLED displays. However, certain nanomaterials, such as carbon nanotubes and metal-organic frameworks, are actually being extensively researched for their high efficiency in safely storing hydrogen for clean energy vehicles and power systems.
Q2657. In the field of electronics, the integration of nanotechnology allows for:
Explanation
Moores Law is the observation that the number of transistors on a microchip doubles approximately every two years. To maintain this pace, transistors must become smaller and smaller. Nanotechnology allows engineers to design and manufacture transistors at the scale of just a few nanometers. This extreme miniaturization is essential for creating faster, more powerful, and more energy-efficient computers and electronic devices.
Q2658. The use of silver nanoparticles (AgNPs) in consumer products like socks and refrigerators is primarily due to their:
Explanation
Silver has been known for its antibacterial properties for centuries. At the nanoscale, silver nanoparticles have a much larger surface area, which significantly enhances their ability to release silver ions that disrupt bacterial cell membranes and enzymes. This makes them highly effective at killing a wide range of bacteria, fungi, and viruses, leading to their widespread use in many consumer products today.
Q2659. Which application uses nanostructured materials to significantly increase the efficiency of converting sunlight into electricity?
Explanation
Nanotechnology is being used to improve the efficiency and lower the cost of photovoltaic cells.
Q2660. Nanoparticles can cross the blood-brain barrier. This property is advantageous for:
Explanation
The blood-brain barrier is a highly selective filtering mechanism that protects the brain from harmful substances in the blood but also prevents most therapeutic drugs from reaching brain tissue. Some specially engineered nanoparticles are small enough and have the right surface properties to cross this barrier. This is a major breakthrough, as it allows for the targeted delivery of drugs.Answer key for these questions
| Q | Correct answer |
|---|---|
| 2651 | (a) Bottom-up approach |
| 2652 | (d) Carbon nanotubes are poorer conductors of electricity than wood. |
| 2653 | (b) Observe and manipulate individual atoms and molecules |
| 2654 | (a) Richard Feynman |
| 2655 | (c) I, II and III |
| 2656 | (a) I, II, III and IV |
| 2657 | (b) Moore’s law to continue by miniaturizing transistors to the nanoscale |
| 2658 | (a) Antimicrobial and antibacterial properties |
| 2659 | (c) Photovoltaic (solar) cells |
| 2660 | (d) Treatment of neurological conditions and brain tumors |
Frequently asked questions
How many RAS Prelims practice MCQs are there on RAS Prelims?
This page has 9654 practice MCQs on the RAS Prelims syllabus. Each has the correct answer, and most have an explanation.
How should I practise MCQs for RAS Prelims?
Attempt each question first, then open the answer and read the explanation. Practise one chapter at a time, note the facts you got wrong and revise them. Repeat the chapter after a few days.
Are these actual RAS Prelims past-paper questions?
No. These are practice questions written for the RAS Prelims syllabus. They follow the pattern the exam uses: factual questions, statement-based questions, match-the-list and assertion-reason.