Fundamentals Of Nanoscience Set 3

Electrical Engineering,

Chemical Engineering

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This set of Fundamentals of NanoScience Multiple Choice Questions & Answers (MCQs) focuses on Fundamentals Of Nanoscience Set 3

Q1 | Where does colloidal solution find application in?
  • in milk industries
  • in chromatic chemical industries
  • in crystallography
  • in textiles
Answer: in milk industries
Explaination:
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.
Q2 | 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.
  • fats
  • amino acids
  • polys
  • r molecules
Answer: amino acids
Explaination:
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.
Q3 | Which of the following form of colloid is considered to be the strongest colloid?
  • gel
  • foam
  • solid sol
  • liquid sol
Answer: solid sol
Explaination:
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.
Q4 | Which of the following form of colloid is considered to be the lightest colloid?
  • gaseous foam
  • solid sol
  • sol
  • liquid sol
Answer: gaseous foam
Explaination:
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.
Q5 | What is the size of normal an amino acid?
  • 1 to 2 nm
  • 2 to 3 nm
  • 4 to 5 nm
  • 2 to 5 nm
Answer: 1 to 2 nm
Explaination:
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.
Q6 | What is called a dispersion phase?
  • it is the main layer
  • it is the secondary layer in which the colloidal particles are dispersed
  • it is the secondary layer
  • it is the basic colloidal layer
Answer: it is the secondary layer in which the colloidal particles are dispersed
Explaination:
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.
Q7 | What is called a dispersion medium?
  • it is where the dispersed phase settles
  • it is where the solute particles settle
  • it is where the dispersed phase is suspended
  • it is the primary medium
Answer: it is where the dispersed phase is suspended
Explaination:
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.
Q8 | Which of the following is not a technique for fabrication of glass fibers?
  • vapor phase oxidation method
  • direct melt method
  • lave ring method
  • chemical vapor deposition technique
Answer: lave ring method
Explaination:
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.
Q9 |                            technique is method of preparing extremely pure optical glasses.
  • liquid phase (melting)
  • radio frequency induction
  • optical attenuation
  • vapor phase deposition (vpd)
Answer: vapor phase deposition (vpd)
Explaination:
vapor phase deposition techniques are used to prepare silica-rich glasses. these glasses exhibit highest transparency and optimal optical properties.
Q10 | Which of the following materials is not used as a starting material in vapor-phase deposition technique?
  • sicl4
  • gecl4
  • o2
  • b2o3
Answer: b2o3
Explaination:
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.
Q11 | P2O5 is used as a                            
  • dopant
  • starting material
  • cladding glass
  • core glass
Answer: dopant
Explaination:
p2o5 is a non silica material. dopants are formed from non silica materials so that refractive index modification is achieved.
Q12 | How many types of vapor-phase deposition techniques are present?
  • one
  • two
  • three
  • four
Answer: two
Explaination:
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.
Q13 |                        uses flame hydrolysis stems from work on soot processes which were used to prepare the fiber with losses below 20 dB/km.
  • outside vapor phase oxidation
  • chemical vapor deposition
  • liquid phase melting
  • crystallization
Answer: outside vapor phase oxidation
Explaination:
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.
Q14 | In modified chemical vapor deposition, vapor phase reactant such as                    pass through a hot zone.
  • halide and oxygen
  • halide and hydrogen
  • halide and silica
  • hydroxides and oxygen
Answer: halide and oxygen
Explaination:
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.
Q15 |                    is the stimulation of oxide formation by means of non-isothermal plasma maintained at low pressure in a microwave cavity surrounding the tube.
  • outside vapor phase oxidation (ovpo)
  • vapor axial deposition (vad)
  • modified chemical vapor deposition (mcvd)
  • plasma-activated chemical vapor deposition (pcvd)
Answer: plasma-activated chemical vapor deposition (pcvd)
Explaination:
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.
Q16 | Only graded index fibers are made with the help of vapor-phase deposition techniques.
  • true
  • false
Answer: false
Explaination:
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.
Q17 | Modified Chemical Vapor Deposition (MCVD) process is also called as an inside vapor phase oxidation (IVPD) technique.
  • true
  • false
Answer: true
Explaination:
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.
Q18 | When does an integrated circuit exhibit greater degree of freedom and electrical performance?
  • in thin and thick film technology
  • in semiconductor technology
  • in semiconductor and films technology
  • in thick film technology only
Answer: in semiconductor and films technology
Explaination:
combining films and semiconductor technology provide a better electrical performance than either technology can provide separately.
Q19 | Give the thickness range of the film used in thin film technology
  • 0.5-2.5 mils
  • 0.02-8 mils
  • 10-20 mils
  • 0.05-0.0 7mils
Answer: 0.02-8 mils
Explaination:
thin films have thickness varying from 50 Å to 20,000 Å.
Q20 | Which technology is used to get cheap resistors and capacitors?
  • thick film technology
  • thin film technology
  • thin and thick film technology
  • none of the mentioned
Answer: thin film technology
Explaination:
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.
Q21 | How is the process of film deposition carried out in cathode sputtering?
  • slower than evaporation method
  • faster than evaporation method
  • similar to same as evaporation method
  • all of the mentioned
Answer: slower than evaporation method
Explaination:
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.
Q22 | How a uniform film with good crystal structure is attained in cathode sputtering process?
  • by hitting high energy particle directly on the substrate
  • allowing less time for the particles to deposit on the substrate
  • high energy particle diffuse through low pressure gas and deposits on the substrate
  • heavy inert gas is used for film deposition on the substrate
Answer: high energy particle diffuse through low pressure gas and deposits on the substrate
Explaination:
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.
Q23 | Which process is used to deposit metals on glass, ceramic and plastic?
  • silk plating technique
  • gas plating technique
  • electroless plating technique
  • electroplating technique
Answer: electroless plating technique
Explaination:
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.
Q24 | Electroplating technique is suitable for
  • making conduction films ceramic
  • coating with considerable thickness
  • coating without use of electric current
  • making conduction films of gold or copper
Answer: making conduction films of gold or copper
Explaination:
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).
Q25 | Which of the following process is involve in thick film technology
  • screen printing
  • ceramic firing
  • silk screening
  • all of the mentioned
Answer: silk screening
Explaination:
silk screening is one of the processes of thin film technology.
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