220+ Fundamentals of NanoScience Solved MCQs

1.

Nanomaterials are the materials with at least one dimension measuring less than

A. 1 nm
B. 10 nm
C. 100 nm
D. 1000 nm
Answer» C. 100 nm
Explanation: a material with at least one of its dimensions measuring less than 100 nm (1 to 100nm) are classified as nanomaterials.
2.

A material with one dimension in Nano range and the other two dimensions are large is called

A. micro-material
B. quantum wire
C. quantum well
D. quantum dot
Answer» C. quantum well
Explanation: such a material with one dimension in nano range and other two large is called quantum well. a material with two of the three dimensions in the nano range and third large is called quantum wire. when all the dimensions are in nano range, it is called quantum dot.
3.

The colour of the nano gold particles is

A. yellow
B. orange
C. red
D. variable
Answer» D. variable
Explanation: the colour of the nano gold particle varies with the size of the particles. it shows different colours like orange, red, purple, or greenish.
4.

The melting point of particles in nano form

A. increases
B. decreases
C. remains same
D. increases then decreases
Answer» B. decreases
Explanation: for the particles in the nano form, the melting point reduces significantly. other chemical properties are also changed as the dimensions of the object comes in the nano range.
5.

The first talk about nano-technology was given by                        

A. albert einstein
B. newton
C. gordon e. moore
D. richard feynman
Answer» D. richard feynman
Explanation: in 1959, richer feynman gave a speech in which he spoke of nano-science and nano-technology. he talked about the possibility of manipulating individual atoms and molecules.
6.

Which of the processes of materials was not described as Nanotechnology?

A. separation
B. creation
C. processing
D. consolidation
Answer» B. creation
Explanation: nanotechnology, as defined by professor n. taniguchi, consists of the processing, separation, consolidation and deformation of materials by one atom or by one molecule. it is used exclusively for the nanomaterials.
7.

The initial tools used to help launch the nanoscience revolution were                        

A. binoculars
B. microscope
C. scanning probe instruments
D. interferometer
Answer» C. scanning probe instruments
Explanation: scanning probe instruments were the initial tools used by the scientist. in these instruments, the probe slides along the surface of the specimen.
8.

When semiconductors are reduced to nanometres they become pure conductors.

A. true
B. false
Answer» B. false
Explanation: when semiconductors are reduced to the nano form their chemical properties change significantly and they become insulators, as there is no more space for free electrons to move.
9.

The major difference between the nano materials compared to the bulk form is the big fraction of the total number of atoms on the surface.

A. true
B. false
Answer» A. true
Explanation: as the bulk material is changed into nano form, the number of atoms on the surface turns out to be a large fraction of the total number of atoms present in the material.
10.

The size of atoms is nearly                          

A. 0.01 nm
B. 0.1 nm
C. 1 nm
D. 10 nm
Answer» B. 0.1 nm
Explanation: the size of the atoms is nearly
11.

The four types of Artificial nanomaterials are

A. carbon-based, non-metallic, composites and ceramics
B. carbon-based, metallic, composites and ceramics
C. carbon-based, non-metallic, composites and dendrimers
D. carbon-based, metallic, composites and dendrimers
Answer» D. carbon-based, metallic, composites and dendrimers
Explanation: artificial nanomaterials can be divided into four categories – carbon-based, metal-based, dendrimers and composites. the other types of nanomaterials are called natural nanomaterials.
12.

Solution of pure buckminsterfullerene has a colour of                        

A. green
B. purple
C. pink
D. yellow
Answer» B. purple
Explanation: solutions of pure c60 have a deep purple colour. they are a class of allotropes of carbon which conceptually are graphene sheets rolled into spheres.
13.

HyFn stands for                      

A. hydrated fluorine
B. hydrolysed fluorine
C. hydrolysed fullerene
D. hydrated fullerene
Answer» D. hydrated fullerene
Explanation: hyfn stands for hydrated fullerene. it is a stable, highly hydrophilic, super-molecular complex consisting of c60 molecules.
14.

Nano sized polymers built from branched units are called                      

A. dendrimers
B. composites
C. carbon-based materials
D. metal-based materials
Answer» A. dendrimers
Explanation: the nano-sized polymers built from branched units are called dendrimers. the dendrimers can be used to perform many chemical functions, such as catalysis, as it has numerous chain ends.
15.

Which property of nanoparticles provides a driving force for diffusion?

A. optical properties
B. high surface area to volume ratio
C. sintering
D. there is no such property
Answer» B. high surface area to volume ratio
Explanation: the nanoparticles provide a high driving force for diffusion, as it has a high surface area to volume ratio. this driving force is even higher at elevated temperatures.
16.

On both ends of the CNTs, which carbon nanostructure is placed?

A. graphite
B. diamond
C. c60
D. benzene
Answer» C. c60
Explanation: carbon nanotubes, cnts, are nanostructures with large application potential. its structure consists of a single sheet of graphite rolled into a tube. the ends of the cnts are capped with c60 hemispheres.
17.

Quantum dots can be used in                    

A. crystallography
B. optoelectronics
C. mechanics
D. quantum physics
Answer» B. optoelectronics
Explanation: quantum dots are basically semiconductor nanoparticles that show a particular colour on illumination by a light. they have unique electrical and optical properties. due to this, they are widely used in optoelectronics.
18.

Vesicle is a type of                      

A. nanostructure
B. nanoparticle
C. nanocrystal
D. supramolecular system
Answer» D. supramolecular system
Explanation: vesicle is a bubble of liquid within another liquid, a supramolecular assembly made up of man different molecules. they can be formed naturally as well as artificially.
19.

The response of a material due to the function of heat is known as                      

A. mechanical property
B. electrical property
C. chemical property
D. thermal property
Answer» D. thermal property
Explanation: mechanical properties deal with the effects of external forces, while electric properties deal with the effect of the flow of electricity, and chemical properties are related to a material’s effects due to reaction with other substances. thermal properties deal with heat and temperature effects on the material.
20.

Specific heat of materials is expressed in terms of                      

A. w/m k
B. j/k
C. j/kg k
D. m3/kg
Answer» C. j/kg k
Explanation: specific heat capacity of a material is an intensive property expressed in terms of j/kg k. thermal conductivity, heat capacity, and specific volume are expressed in terms of w/m k, j/k, and m3/kg correspondingly.
21.

What effect does the addition of thermal energy have on a material?

A. thermal contraction
B. thermal expansion
C. no change
D. reproduction
Answer» B. thermal expansion
Explanation: addition of heat or thermal energy results in an increase in magnitude as a theory of basic laws of thermodynamics. hence, on the addition of thermal energy, thermal expansion occurs.
22.

Which term is used to define the temperature at which a substance changes its status from solid to liquid?

A. boiling point
B. melting point
C. condensation point
D. freezing point
Answer» B. melting point
Explanation: the temperature at which a substance changes from solid state to liquid is known as the melting point; here the temperatures of solid and liquid are in equilibrium. the shift of liquid state to solid is known as the freezing point. the transition from gaseous state to liquid is known as
23.

The melting point of Iron (Fe) is                    

A. 660oc
B. 1084oc
C. 419oc
D. 1538oc
Answer» D. 1538oc
Explanation: the melting point of iron is 1538oc, whereas the melting points of aluminum (al), zinc (zn), and copper (cu) are 660oc, 419oc, and 1084oc in that order.
24.

What effect do thermal variations in volume have on a body?

A. expansion
B. contraction
C. cracking
D. phase transformation
Answer» C. cracking
Explanation: cracking is the effect of thermal variation in the volume of a body. expansion, contraction, and phase transformation are the ways in which these volume changes occur, i.e. they are causes, and not effects.
25.

The temperature at which plastics begin to become softer and defer under a load is known as                    

A. softening point
B. melting point
C. eutectic point
D. heat distortion point
Answer» D. heat distortion point
Explanation: heat distortion point is the temperature at which plastics begin to become softer and defer under a load. the softening point is the temperature at which a flat-ended needle of 1 mm2 penetrates the test same at 1 mm2 depth. eutectic point the temperature at which a mixture freezes or melts. the melting point is the temperature at which the state of the body changes from solid to liquid.
26.

What’s the procedure in Top-down fabrication method?

A. nano-particles -> powder -> bulk
B. powder -> bulk – > nano-particles
C. bulk -> powder – > nano-particles
D. nano-particle – > bulk -> powder
Answer» C. bulk -> powder – > nano-particles
Explanation: top-down approach is the one in which a material of regular size is converted into a nano-particle. in the bottom-up approach, the atoms are joined to form nano-particles.
27.

Which of the following is an example of Bottom Up approach?

A. attrition
B. colloidal dispersion
C. milling
D. etching
Answer» B. colloidal dispersion
Explanation: colloidal dispersion is an example of bottom up approach in the synthesis of nano particles. attrition, milling and etching are typical top down methods.
28.

For milling operations, what kind of environment is preferred?

A. acidic
B. basic
C. active
D. inert
Answer» D. inert
Explanation: milling is the process of particle size reduction with the objective of mixing or blending and change of particle size. an inert environment is preferred for this process.
29.

What kind of metals are used for milling operations?

A. soft and brittle
B. soft and elastic
C. hard and brittle
D. hard and elastic
Answer» C. hard and brittle
Explanation: for the milling operation, normally hard brittle materials with fracture, deform and cold weld are used. the reason for choosing dense materials is the fact that the kinetic energy of balls depends upon their mass and velocity.
30.

The following flow chart is for which method?

A. milling
B. attrition
C. pattering
D. microfabrication
Answer» D. microfabrication
Explanation: the given process is the process of microfabrication. the water is prepared and then photoresist is applied. the product is exposed to the uv light which after a series of processes, results in the fabrication of nanomaterials.
31.

CVD stands for                          

A. carbon vapour density
B. chemical vapour density
C. chemical vapour deposition
D. carbon vapour deposition
Answer» C. chemical vapour deposition
Explanation: chemical vapour deposition, or cvd, is a chemical process used to produce high-purity, high-performance solid materials. the process is often used to produce carbon nanotubes.
32.

Photolithography is a type of patterning technique.

A. true
B. false
Answer» A. true
Explanation: photolithography has been the predominant patterning technique for a long time. it will require the use liquid immersion and a host of resolution enhancement technologies.
33.

Chemical solution deposition is also known as                          

A. sol-gel
B. cvd
C. plasma spraying
D. laser pyrolysis
Answer» A. sol-gel
Explanation: sol-gel, or chemical solution deposition, is used primarily for the fabrication of material starting from a chemical solution that acts as the precursor for an integrated network.
34.

Typical precursor used in sol-gel are

A. metal oxides
B. metal dioxides
C. metal alkoxides
D. metal fluorides
Answer» C. metal alkoxides
Explanation: metal alkoxides and metal chlorides are basically used as precursors in sol- gel. furthermore, a colloidal suspension is formed when they undergo hydrolysis or poly- condensation.
35.

The following is a bottom-up process.

A. true
B. false
Answer» A. true
Explanation: sol-gel is a bottom-up approach in which a precursor is used to for wither a network or a colloidal suspension, so as to form desired nanoparticles.
36.

Particles of ZrO2, Y2O2 and Nano whiskers have been produced by                      

A. sol-gel
B. cvc
C. plasma spraying
D. laser pyrolysis
Answer» B. cvc
Explanation: cvc stands for chemical vapour condensation. it involves pyrolysis of vapours of metal organic precursors in a reduced pressure atmosphere.
37.

Which gas serves as buffer gas in Laser ablation?

A. nitrogen
B. oxygen
C. helium
D. neon
Answer» C. helium
Explanation: laser ablation has been extensively used for the preparation of nanoparticles. in the device, there is a pulsed flow of helium gas. it serves as a buffer gas in which clusters of the target material form, thermalize.
38.

Which of the following is an unconventional process of machining?

A. milling
B. usm
C. drilling
D. none of the mentioned
Answer» B. usm
Explanation: usm stands for ultrasonic machining process and it is an unconventional process of machining.
39.

Ultrasonic machining process can be used for

A. conductors
B. insulators
C. metals
D. all of the mentioned
Answer» D. all of the mentioned
Explanation: ultrasonic machining is more versatile and can be used for the metal as well as non metal.
40.

Which of the following is a conventional process of machining?

A. electro chemical machining
B. electron beam machining
C. ultrasonic machining
D. none of the mentioned
Answer» D. none of the mentioned
Explanation: all of the mentioned are unconventional process of machining.
41.

For machining of plastic material which of the unconventional process can be used effectively?

A. electro chemical machining
B. electron beam machining
C. ultrasonic machining
D. none of the mentioned
Answer» C. ultrasonic machining
Explanation: ultrasonic machining is more versatile and can be used for the metal as well as non metal.
42.

Material removal rate in USM increases with

A. decrease in volume of work material per impact
B. increase in volume of work material per impact
C. decrease in frequency
D. decrease in number of particle making impact per cycle
Answer» B. increase in volume of work material per impact
Explanation: material removal rate in usm is proportional to the volume of work material per impact.
43.

Material removal rate in USM increases with

A. decrease in volume of work material per impact
B. decrease in volume of work material per impact
C. decrease in frequency
D. increase in number of particle making impact per cycle
Answer» D. increase in number of particle making impact per cycle
Explanation: material removal rate in usm is proportional to the number of particle making impact per cycle.
44.

Material removal rate in USM increases with

A. decrease in volume of work material per impact
B. decrease in volume of work material per impact
C. increases in frequency
D. decreases in the number of particle making impact per cycle
Answer» C. increases in frequency
Explanation: material removal rate in ultrasonic machining is proportional to frequency.
45.

Element of machine which is used to convert high frequency electrical impulse into mechanical vibration in USM is known as

A. tool
B. feeding unit
C. transducer
D. none of the mentioned
Answer» C. transducer
Explanation: transducer is a device which is used to convert one form of energy to other.
46.

Which of the following elements of USM is used to apply working force during machining operation?

A. tool
B. feeding unit
C. transducer
D. none of the mentioned
Answer» B. feeding unit
Explanation: feeding unit is used to apply working force during a machining operation.
47.

Material removal rate in USM increases with

A. decrease in amplitude
B. decrease in grain size of abrasives
C. decrease in frequency
D. increase in amplitude
Answer» D. increase in amplitude
Explanation: material removal rate in ultrasonic machining is proportional to amplitude.
48.

3 COLLOIDAL ROUTES, SELF-ASSEMBLY

A. 10-20 nm
B. more than 20 nm
C. less than 10 nm
D. 30 to 50 nm
Answer» A. 10-20 nm
Explanation: since colloidal are intermediate between powdered particles and suspension particles, they have a size in between these particles of about 10 to 20 nm. these are considered to be intermediate size of molecules.
49.

Which of the following is a characteristic of a colloid?

A. it forms 2 layers with a solution
B. it forms turbid layers
C. it forms heterogeneous layer
D. it forms a homogeneous layer
Answer» B. it forms turbid layers
Explanation: since a colloidal particle does not from a single layer with solvents, the only possibility is to form a turbid layer where the solution is an intermediate between a miscible and immiscible solution.
50.

Where does colloidal solution find application in?

A. in milk industries
B. in chromatic chemical industries
C. in crystallography
D. in textiles
Answer» A. in milk industries
Explanation: since colloidal solutions can easily be emulsified with the help of emulsifying agents such as ethylene dichloride, it can find its major application in the field of dairy industries.
51.

During an experiment, accidently iodine got mixed up with a biological sample of proteins and polys. Identify the smallest colloid that can be obtained during the process of separation.

A. fats
B. amino acids
C. polys
D. r molecules
Answer» B. amino acids
Explanation: given that the solution of iodine got mixed up with milk sample, we know milk is already a colloidal solution of polymers like amino acids, proteins, fats, vitamins etc, the smallest among all these colloidal particles is amino acids.
52.

Which of the following form of colloid is considered to be the strongest colloid?

A. gel
B. foam
C. solid sol
D. liquid sol
Answer» C. solid sol
Explanation: we know that solid sol is the colloidal solution of a solid and a solid. since there is a mixture of solid and solid, the bond between them is quite strong. thus it is considered to be the strongest colloid.
53.

Which of the following form of colloid is considered to be the lightest colloid?

A. gaseous foam
B. solid sol
C. sol
D. liquid sol
Answer» A. gaseous foam
Explanation: we know that the gaseous foam is the colloidal solution of gaseous molecules and liquid. thus there exists a lighter bond between the particles. thus this is considered as the lightest colloid.
54.

What is the size of normal an amino acid?

A. 1 to 2 nm
B. 2 to 3 nm
C. 4 to 5 nm
D. 2 to 5 nm
Answer» A. 1 to 2 nm
Explanation: we know that amino acids are nothing but single structure monomers of proteins. thus they are visible only under an ultra microscope due to is an extreme small size in the range of nano meters. their size ranges from 1 to 2 nm.
55.

What is called a dispersion phase?

A. it is the main layer
B. it is the secondary layer in which the colloidal particles are dispersed
C. it is the secondary layer
D. it is the basic colloidal layer
Answer» B. it is the secondary layer in which the colloidal particles are dispersed
Explanation: since the colloidal particles require a layer in which it has to be dispersed, the dispersion phase is considered to be a second layer. the dispersion phase is generally a solvent.
56.

What is called a dispersion medium?

A. it is where the dispersed phase settles
B. it is where the solute particles settle
C. it is where the dispersed phase is suspended
D. it is the primary medium
Answer» C. it is where the dispersed phase is suspended
Explanation: since to form a stable colloidal solution, the dispersed phase requires a stable solvent medium is required. this is the condition in which equilibrium is achieved.
57.

Which of the following is not a technique for fabrication of glass fibers?

A. vapor phase oxidation method
B. direct melt method
C. lave ring method
D. chemical vapor deposition technique
Answer» C. lave ring method
Explanation: lave ring method refers to the deposition of a crystalline layer on a substrate. all the other methods, except lave ring method, refer to optical fiber fabrication.
58.

                           technique is method of preparing extremely pure optical glasses.

A. liquid phase (melting)
B. radio frequency induction
C. optical attenuation
D. vapor phase deposition (vpd)
Answer» D. vapor phase deposition (vpd)
Explanation: vapor phase deposition techniques are used to prepare silica-rich glasses. these glasses exhibit highest transparency and optimal optical properties.
59.

Which of the following materials is not used as a starting material in vapor-phase deposition technique?

A. sicl4
B. gecl4
C. o2
D. b2o3
Answer» D. b2o3
Explanation: in vapor-phase deposition technique, starting materials are volatile organic compounds. these materials are distilled to reduce the concentration of transition metal impurities. b2o3 is used as a dopant.
60.

P2O5 is used as a                            

A. dopant
B. starting material
C. cladding glass
D. core glass
Answer» A. dopant
Explanation: p2o5 is a non silica material. dopants are formed from non silica materials so that refractive index modification is achieved.
61.

How many types of vapor-phase deposition techniques are present?

A. one
B. two
C. three
D. four
Answer» B. two
Explanation: vapor-phase deposition techniques are divided into two types. the two types are flame hydrolysis and chemical vapor deposition (cvd). further, these two types are subdivided into two more sections.
62.

                       uses flame hydrolysis stems from work on soot processes which were used to prepare the fiber with losses below 20 dB/km.

A. outside vapor phase oxidation
B. chemical vapor deposition
C. liquid phase melting
D. crystallization
Answer» A. outside vapor phase oxidation
Explanation: outside vapor phase oxidation is a type of vapor flame hydrolysis. it was originally developed by hyde. in this process, the glass composition is deposited from a ‘soot’ generated by hydrolyzing the halide vapors in an oxygen-hydrogen flame.
63.

In modified chemical vapor deposition, vapor phase reactant such as                    pass through a hot zone.

A. halide and oxygen
B. halide and hydrogen
C. halide and silica
D. hydroxides and oxygen
Answer» A. halide and oxygen
Explanation: halide and oxygen are passed through the hot zone during chemical vapor deposition. glass particles formed during this travel are deposited on the walls of silica tube which are moved back and forth allowing the particles to deposit layer by layer.
64.

                   is the stimulation of oxide formation by means of non-isothermal plasma maintained at low pressure in a microwave cavity surrounding the tube.

A. outside vapor phase oxidation (ovpo)
B. vapor axial deposition (vad)
C. modified chemical vapor deposition (mcvd)
D. plasma-activated chemical vapor deposition (pcvd)
Answer» D. plasma-activated chemical vapor deposition (pcvd)
Explanation: pcvd method was first developed by cuppers and koenig’s. it involves a plasma-induced chemical vapor deposition inside a silica tube. it is different from mcvd process as it involves stimulation of oxide formation by means of non-isothermal plasma.
65.

Only graded index fibers are made with the help of vapor-phase deposition techniques.

A. true
B. false
Answer» B. false
Explanation: vapor phase deposition techniques are used for preparation of both step- index and graded index fibers. these techniques provide fibers with low attenuation losses. also, it gives similar performance for the fabrication of both single mode and multimode fibers.
66.

Modified Chemical Vapor Deposition (MCVD) process is also called as an inside vapor phase oxidation (IVPD) technique.

A. true
B. false
Answer» A. true
Explanation: mcvd process was developed by bell telephone laboratories and southampton university, uk. it is called as inside vapor phase oxidation (ivpo) as it takes place inside the silica tube at the temperatures between 1400 and 1600 degrees celsius.
67.

When does an integrated circuit exhibit greater degree of freedom and electrical performance?

A. in thin and thick film technology
B. in semiconductor technology
C. in semiconductor and films technology
D. in thick film technology only
Answer» C. in semiconductor and films technology
Explanation: combining films and semiconductor technology provide a better electrical performance than either technology can provide separately.
68.

Give the thickness range of the film used in thin film technology

A. 0.5-2.5 mils
B. 0.02-8 mils
C. 10-20 mils
D. 0.05-0.0 7mils
Answer» B. 0.02-8 mils
Explanation: thin films have thickness varying from 50 Å to 20,000 Å.
69.

Which technology is used to get cheap resistors and capacitors?

A. thick film technology
B. thin film technology
C. thin and thick film technology
D. none of the mentioned
Answer» B. thin film technology
Explanation: thick film technology produces cheap and rugged components, whereas thin film technology provides greater precision in manufacturing but is quite expensive. the processing equipment for thick film circuit is relatively inexpensive and is easy to use.
70.

How is the process of film deposition carried out in cathode sputtering?

A. slower than evaporation method
B. faster than evaporation method
C. similar to same as evaporation method
D. all of the mentioned
Answer» A. slower than evaporation method
Explanation: cathode sputtering and vacuum evaporation uses identical system. however, the process of film deposition in cathode sputtering is slower than evaporation method. since depositing a micron-thick film takes minutes to hours, compared to seconds to minutes for evaporation.
71.

How a uniform film with good crystal structure is attained in cathode sputtering process?

A. by hitting high energy particle directly on the substrate
B. allowing less time for the particles to deposit on the substrate
C. high energy particle diffuse through low pressure gas and deposits on the substrate
D. heavy inert gas is used for film deposition on the substrate
Answer» C. high energy particle diffuse through low pressure gas and deposits on the substrate
Explanation: the process of cathode sputtering is performed at a low pressure (about 10-12 torr). so, when the high energy particle landing on the substrate actually results in a very uniform film and adhesion.
72.

Which process is used to deposit metals on glass, ceramic and plastic?

A. silk plating technique
B. gas plating technique
C. electroless plating technique
D. electroplating technique
Answer» C. electroless plating technique
Explanation: in electroless plating, a metal ion in solution is reduced to the free metal and deposited as a metallic coating without the use of a coating without the use of an electric current. thus, this process is used in plating on glass, ceramic and plastic.
73.

Electroplating technique is suitable for

A. making conduction films ceramic
B. coating with considerable thickness
C. coating without use of electric current
D. making conduction films of gold or copper
Answer» D. making conduction films of gold or copper
Explanation: electroplating is a process of coating an object with one or more layers of different metal. when dc is passed through the electrolytic solution, the positive metal ions migrate from anode (metal) and deposit on the cathode (substrate).
74.

Which of the following process is involve in thick film technology

A. screen printing
B. ceramic firing
C. silk screening
D. all of the mentioned
Answer» C. silk screening
Explanation: silk screening is one of the processes of thin film technology.
75.

An ancient process used till today for production of circuit films is,

A. silk screening technique
B. surface mount technology
C. ceramic printing technique
D. screen printing technique
Answer» D. screen printing technique
Explanation: the process of screen printing pattern is an ancient one. the egyptian used this technique thousands of years ago to decrease potter and wall of building.
76.

What is the advantage of using Surface Mount Technology?

A. all of the mentioned
B. low power consumption
C. reduces heat dissipation in components
D. use leaded or leadless components
Answer» D. use leaded or leadless components
Explanation: surface mount technology utilizes micro-miniature leaded or leadless components called surface mount device (smd) which are directly soldered to the specified areas on the surface without hole. also, the compact size of smds reduces the area in pcb and increases the packing density.
77.

Which of the following is an example of top- down approach for the preparation of nanomaterials?

A. gas phase agglomeration
B. molecular self-assembly
C. mechanical grinding
D. molecular beam epitaxy
Answer» C. mechanical grinding
Explanation: mechanical grinding is an example of top-down approach for the preparation of nanomaterials. all the other options are the example of bottom-up approach.
78.

Which of the following is an example of bottom-up approach for the preparation of nanomaterials?

A. etching
B. dip pen nano-lithography
C. lithography
D. erosion
Answer» B. dip pen nano-lithography
Explanation: dip pen nanolithography is an example of bottom-down approach for the preparation of nanomaterials. all the other options are the example of top-down approach.
79.

The properties like melting point, solubility, color, etc changes on varying the                        

A. size
B. composition
C. surface properties
D. none of the mentioned
Answer» A. size
Explanation: the properties like melting point, solubility, color, etc changes on varying the size of the particles. these all are the physical properties and depends upon the physical characteristics of the particle.
80.

The properties like dispersibility, conductivity, etc changes on varying the

A. size
B. composition
C. surface properties
D. none of the mentioned
Answer» C. surface properties
Explanation: the properties like dispersibility, conductivity, etc changes on varying the surface properties of the nanoparticle. these all are the chemical properties and depend upon the surface characteristics of the particle.
81.

Quantum confinement results in

A. energy gap in semiconductor is proportional to the inverse of the square root of the size
B. energy gap in semiconductor is proportional to the inverse of the size
C. energy gap in semiconductor is proportional to the square of size
D. energy gap in semiconductor is proportional to the inverse of the square of size
Answer» D. energy gap in semiconductor is proportional to the inverse of the square of size
Explanation: the energy gap in a semiconductor is proportional to the inverse of the square of the size. this effect is a result of quantum confinement.
82.

Which of the following is the principal factor which causes the properties of nanomaterials to differ significantly from other materials?

A. size distribution
B. specific surface feature
C. quantum size effects
D. all of the mentioned
Answer» D. all of the mentioned
Explanation: size distribution, specific surface feature and quantum size effects are the principal factor which causes the properties of nanomaterials to differ significantly from other materials.
83.

Select the incorrect statement from the following options.

A. self-assembly is a top-down manufacturing technique
B. in self-assembly, weak interactions play very important role
C. self-assembling molecules adopt an organised structure which is thermodynamically more stable than the single, unassembled components
D. compared to the isolated components, the self-assembled structure has a higher order
Answer» A. self-assembly is a top-down manufacturing technique
Explanation: self-assembly is a bottom-down manufacturing technique. all the other options are correct. in self-assembly, weak interactions play very important role, self-assembling
84.

Which of the following is the application of nanotechnology to food science and technology?

A. agriculture
B. food safety and biosecurity
C. product development
D. all of the mentioned
Answer» D. all of the mentioned
Explanation: the application of nanotechnology to food science and technology are agriculture, food safety and biosecurity, product development, food processing and ingredient technologies.
85.

What are the advantages of nano-composite packages?

A. lighter and biodegradable
B. enhanced thermal stability, conductivity and mechanical strength
C. gas barrier properties
D. all of the mentioned
Answer» D. all of the mentioned
Explanation: the advantages of nano- composite packages are-lighter and biodegradable, enhanced thermal stability, conductivity, mechanical strength and gas barrier properties.
86.

The efficiency of today’s best solar cell is about                        

A. 15-20%
B. 40%
C. 50%
D. 75%
Answer» B. 40%
Explanation: the efficiency of today’s best solar cells is about 40%. a solar cell or photovoltaic cell is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect.
87.

The configuration of Buckminsterfullerene is

A. 12 hexagons and 22 pentagons
B. 18 hexagons and 15 pentagon
C. 20 hexagon and 12 pentagon
D. 15 hexagon and 15 pentagon
Answer» C. 20 hexagon and 12 pentagon
Explanation: buckminsterfullerene, commonly known as fullerene, consists of 20 hexagons and 12 pentagons, which are arrayed such that no two pentagons share a common side.
88.

C60 is soluble in                          

A. water
B. ammonia
C. hcl
D. benzene
Answer» D. benzene
Explanation: c60 molecules are held together by weak van der waal’s forces. they are insoluble in ionic solvents like water, ammonia and hcl, as it is non-ionic. as it is an organic molecule, it is soluble in benzene.
89.

CNTs stands for                          

A. carbon nanotubes
B. carbon nanotechnology
C. carbon nanoscience and technology
D. carbon nine technology
Answer» A. carbon nanotubes
Explanation: carbon nanotubes, cnts, are nanostructures with large application potential. its structure consists of a single sheet of graphite rolled into a tube.
90.

CNTs are capped on both ends with which carbon nanostructure?

A. graphite
B. diamond
C. c60
D. benzene
Answer» C. c60
Explanation: carbon nanotubes are basically a single sheet of graphite, which is rolled into a tube. the ends of the cnts are covered by the c60 hemispheres. such is the construction of a cnt.
91.

The metallic tubes have which kind of structure?

A. armchair
B. chiral
C. boat
D. achiral
Answer» A. armchair
Explanation: the cnts are often a mixture of semiconducting and metallic tubes. while the metallic tubes have armchair structure, the semiconducting tubes have a chiral structure.
92.

The carbon tubes have high conductivity.

A. true
B. false
Answer» A. true
Explanation: the reason for the high conductivity of the carbon nanotubes is that they have very few defects to scatter electrons and therefore show very low resistance.
93.

Carbon nanotubes display magnetoresistance at low temperature.

A. true
B. false
Answer» A. true
Explanation: magnetoresistance is the phenomenon in which the resistance of a material changes on the application of a magnetic field. carbon nanotubes display this property at low temperature. in fact, it shows negative magnetoresistance as the resistance decreases with an increasing magnetic field.
94.

Identify the process.

A. synthesis of c60
B. synthesis of cnts
C. chemical vapour deposition
D. carbon discharge
Answer» B. synthesis of cnts
Explanation: the given figure shows the schematic diagram for synthesis of cnt by laser evaporation. the quartz tube is heated to 1200°. a water called copper collection is present at the end to cool it down.
95.

The main purpose of CNTs in fuel cells is

A. production of energy
B. active medium
C. catalyst
D. storage
Answer» D. storage
Explanation: carbon nanotubes are useful in
96.

The figure shows a FET using CNT. Identify CNT.

A. bucky balls
B. soccer balls
C. cricket balls
D. tennis balls
Answer» A. bucky balls
Explanation: spherical fullerenes are otherwise called as the bucky balls. they resemble to the
97.

The fullerenes are composed with                    

A. graphene sheets
B. graphite
C. lead
D. other carbon materials
Answer» A. graphene sheets
Explanation: the fullerenes are composed with stalked graphene sheets. the fullerenes are similar to the structure of graphite. the only difference is they can be n sphere, tube or ellipsoid but graphene is layers.
98.

In fullerenes, the graphene sheets are linked with                  

A. hexagonal rings
B. octagonal rings
C. trigonal rings
D. decagonal rings
Answer» A. hexagonal rings
Explanation: the fullerenes are composed with the stalked graphite sheets that are linked with the hexagonal ring. they may also be linked with the pentagonal and heptagonal rings sometimes.
99.

The smallest bucky ball cluster is                    

A. c6
B. c8
C. c10
D. c20
Answer» D. c20
Explanation: the smallest bucky ball cluster is
100.

Hollow tubes of very small dimensions are called as                            

A. mega tubes
B. carbon nano tubes
C. bucky ball clusters
D. polymers
Answer» B. carbon nano tubes
Explanation: hallow tubes of very small dimensions are called the carbon nano tubes having single or multiple walls. potential applications are in electronic industry.
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