Miscellaneous Physics Part-1

Total Questions: 50

21. A particle having at least one dimension less than 10⁻⁹ to 10⁻⁷ metre is known as — [R.A.S./R.T.S. (Pre) 2018]

(a) Micro particle
(b) Milli particle
(c) Nano particle
(d) Macro particle

Correct Answer: (c) Nano particle

Solution:

A nanoparticle is generally defined as a particle with at least one dimension in the range of 1 to 100 nanometers ( $1 0⁻⁹$ to $1 0⁻⁷$ meters). Since $1 0⁻⁷$ meters is the upper limit for at least one dimension, a particle with a dimension less than this falls within the nanoscale.

22. The size of the nanoparticle ranges between: [Uttarakhand P.C.S. (Pre) 2012]

(a) 100 nm to 1000 nm
(b) 0.1 nm to 1 nm
(c) 1 nm to 100 nm
(d) 0.01 nm to 0.1 nm

Correct Answer: (c) 1 nm to 100 nm

Solution:

23. Consider the following statements: [I.A.S. (Pre) 2022]

Other than those made by humans, nanoparticles do not exist in nature.
Nanoparticles of some metallic oxides are used in the manufacture of some cosmetics.
Nanoparticles of some commercial products which enter the environment are unsafe for humans.

Which of the statements given above is/are correct?

(a) 1 only
(b) 3 only
(c) 1 and 2
(d) 2 and 3

Correct Answer: (d) 2 and 3

Solution:Nanoparticles (NPs) are tiny materials having sizes ranging from 1 to 100 nm. Many of these are made by humans, but they are also naturally produced by many cosmological, geological, meteorological, and biological processes.
A significant fraction (by number, if not by mass) of interplanetary dust, that is still falling on the Earth at the rate of thousands of tonnes per year, is in the nanoparticle range, and the same is true of atmospheric dust particles. Many viruses also have diameters in the nanoparticle range.
Metal oxides in nanoparticle form such as zinc oxide and titanium dioxide now appear on the ingredient lists of household products as common and diverse as cosmetics, sunscreens, toothpastes, and medicines.
NPs of some commercial products which enter the environment are unsafe for humans. Inhaling certain nano-sized particles may result in local lung inflammation, allergic responses, or harmful effects on genes. Some particles may enter the bloodstream and accumulate in organs like the liver and spleen. Nanoparticulate matter is able to enter cells, which might, in turn, lead to direct and indirect genotoxic effects.

24. 'Nano plug' refers to: [U.P.P.C.S. (Pre) (Re. Exam) 2015]

(a) A small bullet
(b) A small hearing aid
(c) A small rocket launcher
(d) None of the above

Correct Answer: (b) A small hearing aid

Solution:'Nano plug' refers to a small hearing aid. It is so tiny that it is almost undetectable. Nano plug is comprised of micro-components and a nano-battery. It can be programmed by using software running on a computer, the result of which can be downloaded directly to the device via a cable.

25. Which one of the following statements is correct? [R.A.S/R.T.S. (Pre) 2013]

(a) Nanoear can detect sound levels as low as -120 dB
(b) Nano-ear can detect sound as low as -60 dB
(c) Nanoear consists of a single silica nanoparticle
(d) Nanoear consists of a single silver nanoparticle

Correct Answer: (b) Nano-ear can detect sound as low as -60 dB

Solution:In 2012, the scientists of Munich University, Germany developed the first-ever 'nano-ear' capable of detecting sound on a microscopic length scale with an estimated sensitivity that is six orders of magnitude below the threshold of human hearing. The device is based on an optically trapped gold nanoparticle and it can detect sound/vibrations at a power level as low as -60 dB.

The "nano-ear" described in the research utilizes a single gold nanoparticle, not silica or silver.

26. Who among the following gave the term 'Nanotechnology' and when? [Uttarakhand P.C.S. (Pre) 2016]

(b) Norio Taniguchi - 1974
(a) Richard Feynman - 1959
(c) Eric Drexler - 1986
(d) Sumio Iijima - 1991

Correct Answer: (b) Norio Taniguchi - 1974

Solution:Norio Taniguchi was a professor at Tokyo University. He used the term 'Nanotechnology' for the first time in his research paper published in 1974.

27. With reference to carbon nanotubes, consider the following statements: [I.A.S. (Pre) 2020]

They can be used as carriers of drugs and antigens in the human body.
They can be made into artificial blood capillaries for an injured part of the human body.
They can be used in biochemical sensors.
Carbon nanotubes are biodegradable.

Which of the statements given above are correct?

(a) 1 and 2 only
(b) 2, 3 and 4 only
(c) 1, 3 and 4 only
(d) 1, 2, 3, and 4

Correct Answer: (c) 1, 3 and 4 only

Solution:Carbon nanotubes (CNTs) are allotropes of carbon made from graphite and constructed in cylindrical tubes with nanometre diameters. CNTs have been successfully applied in pharmacy and medicine due to their high surface area, which is capable of absorbing or conjugating with a wide variety of therapeutic and diagnostic agents (drugs, genes, vaccines, antibodies, biosensors, etc.).
They have proven to be an excellent vehicle for drug delivery directly into cells without metabolism by the body. NASA has demonstrated biochemical sensors using carbon nanotube arrays. As per a September 2019 report from The Hindu, researchers fabricated a highly sensitive carbon nanotube-based sensor capable of detecting multidrug-resistant myeloid leukemia cells.
Statement 4 is also correct as multiple types of microbes and enzymes have the ability to biodegrade carbon nanotubes. However, as per a 2015 study, non-functionalised carbon nanotubes are not blood-compatible as they stimulate blood platelet activation, leading to blood clotting. Thus, statement 2 is incorrect.

28. With reference to the use of nanotechnology in the health sector, which of the following statements is/are correct? [I.A.S. (Pre) 2015]

Targeted drug delivery is made possible by nanotechnology.
Nanotechnology can largely contribute to gene therapy.

Select the correct answer using the code given below:

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Correct Answer: (c) Both 1 and 2

Solution:Nanotechnology is a rapidly expanding area of research with huge potential in many sectors ranging from healthcare to construction and electronics. In medicine, it promises to revolutionize drug delivery, gene therapy, diagnostics, and many areas of research, development, and clinical application.
Discovery of nanomedicine has given rise to nanoparticles, through which better target-specific drug and gene delivery is possible. Nanotechnology enables us to deliver drugs in the form of dendrimers, liposomes, nanoshells, emulsions, nanotubes, quantum dots, etc., for the manipulation of various diseases and their metabolic pathways. It is of great importance in the treatment and diagnosis of cancer.

29. The most important property of nanomaterials is — [R.A.S./R.T.S. (Pre) 2013]

(a) Force
(b) Friction
(c) Pressure
(d) Temperature

Correct Answer: (b) Friction

Solution:Friction is the most important property of nanomaterials.

High Surface Area to Volume Ratio: Nanomaterials possess an exceptionally large surface area. This increased surface area leads to a greater number of atoms on the surface, which significantly enhances surface-related properties.
Enhanced Interactions: This high surface area results in increased interaction with the surrounding environment.
Dominance of Surface Forces: At the nanoscale, surface forces like van der Waals forces become much more significant compared to bulk forces like gravity.

30. If in a material one dimension is reduced to the Nano range while the other two dimensions remain large, the structure so obtained is known as: [Rajasthan P.C.S. (Pre) 2023]

(a) Quantum step
(b) Quantum well
(c) Quantum dot
(d) Quantum wire

Correct Answer: (b) Quantum well

Solution:If one dimension is reduced to the nano range while the other dimensions remain large, we obtain a structure known as a quantum well. If two dimensions are so reduced and one remains large, the resulting structure is referred to as a quantum wire. The extreme case of this process of size reduction, where all three dimensions reach the low nanometer range, is called a quantum dot.

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