M.Sc. (Semester IV) (CGPA) Examination Oct/Nov-2017
Materials Science
NANO SCIENCE NANO TECHNOLOGY
Day Date: Friday, 24-11-2017 Max. Marks: 70
Time: 02.30 PM to 05.00 PM
Instructions: Q. and Q. are compulsory.
Answer any three questions from Q.3 to Q.7.
All questions carry equal marks.
Q.1

Objective questions:
Choose the correct alternatives:-
14
08
The surface area to volume ratio of a sphere with radius 30 nm is.
108 109
107 106
In bottom up approach the building blocks can be.
Atoms Molecules
Clusters All above
If the size of the metal nanoparticles decreases then the position of
the SPR peak.
Shift towards lower wavelength
Shift towards higher wavelength
Remains same
None of these
Nanotubes usually form in bundles. Which is the best description of
such a bundle?
The tubes are aligned, axes parallel, with van der Waals forces
operating between adjacent tubes.
The tubes are connected together by covalent C-C bonds.
The tubes are randomly organized, with the axes of the tubes
lying in random directions
The bundles are of discrete sizes, and dipole-dipole forces hold
the tubes together
The basic principle of AFM is.
Change in force due to change in distance
Change in current due to change in distance
Change in shape due to change in distance
Change in size due to change in distance
In SEM the morphology of the sample is achieved with the help of.
Secondary electrons Primary electrons
Emitted electrons Photo electrons
For emission of the electrons from the metal surface the minimum
required energy is.
Work function of the metal.
Binding energy of the electron
Kinetic energy of the electron
None of these
Page 2 of 2
SLR-MO-538
If an electron is confined in limited space then the allowed energy
states are.
Continuous Discrete
Limited None
State True or False/ Fill in the blanks: 06
In AFM, the sample is mounted on a piezoelectric tube.
The ball milling is a top down method.
The SPR observed for insulator nanoparticles.
The melting point of the nanoparticles is smaller than the bulk sized
particle.
The Drude model neglects any long-range interaction between the
electron and the ions or between the electrons.
The electron mobility in semiconductors can be greatly decreased by
the formation of polarons.
Q.2 Write short notes: 14
Quantum dots 05
Drude model 05
Single electron transistor 04
Q.3 Describe principle and operation of TEM. 10
Explain how a CNT can be bent to a ring. 04
Q.4 Explain how endo-fullerenes can be used as one-dimensional metalsemiconductor
junctions?
10
Explain the basic difference between a PVD and CVD process. 04
Q.5 How do you expect the conductivity to vary in an intrinsic semiconductor
with increasing temperature?
07
How do you expect the conductivity to vary in a metallic conductor with
increasing temperature
07
Q.6 "Bottom-up technique is more convenient for nano fabrication" Explain. 10
Why is spatial resolution of STM better than AFM? 04
Q.7 "Template-assisted synthesis is a very efficient tool to grow highly
ordered and nano-wires/rods" Explain.
10
State the merits and demerits of solution-based nano-fabrication
techniques.