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Unit 1 ULTRASONICS
Part – A
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What are Ultrasonic waves?
Mention any 4 properties of ultrasonic waves.
What is magnetostriction effect?
What is meant by piezoelectric effect?
What are the different methods used for the production of ultrasonic waves?
Mention some uses of the ultrasonic waves.
What is SONAR? Explain how ultrasonic waves are used in SONAR.
What is meant by Sonogram?
What is acoustic grating?
Name any four methods of detection of ultrasonic waves.
What are the different scanning methods used in ultrasonic?
How are ultrasonic waves used to measure depth of sea?
What is cavitation? Mention its use.
A quartz crystal of thickness 0.001m is vibrating at resonance. Calculate the fundamental frequency. Density of quartz crystal
2.650x108 Kg/m3 and Young’s modulus for quartz 7.9x1010N/m2.
15. A ultrasonic generator consists of a quartz plate of thickness 0.7 mm and density 2800 kg/m 3. Find the fundamental
frequency of ultrasonic waves if the Young’s modulus of quartz is 8.8 x 10 10 N/m2.
16. Calculate the frequency of ultrasonic waves that can be generated by a nickel rod of length 4 cm. (Young’s modulus of nickel
= 207 Gpa and density of nickel= 8900 Kg/m3)
Part – B
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Explain with neat circuit diagram, the generation of ultrasonic waves using magnetostriction method and list out
some properties of ultrasonic waves.(12+4)
Explain how ultrasonic waves can be produced by using piezoelectric crystal and write any four applications of
ultrasonic.(12+4)
With theory, explain the method of determination of velocity of ultrasonic waves in liquid using acoustic grating.(8)
Explain how ultrasonic waves are used in the following engineering applications.(4+8)
i.
SONAR
ii.
Detection of Flaw in metals.
What is Doppler Effect? Explain how the Doppler effect is used in ultrasonic to study fetal heart movement.(10)
With necessary block diagram, explain the functioning of ultrasonic flaw detector. Explain the different scanning
methods.(16)
(i) Explain in detail various scanning mode using ultrasonic waves. (8)
(ii) Write a note on sonogram with neat sketch. (8)
UNIT 2 LASER AND ITS APPLICATION
Part – A
1. What does the term LASER stands for?
2. What are the characteristics of laser beam?
3. What is mean by coherence in laser light?
4. Distinguish between spontaneous and stimulated emission.
5. What are Einstein’s coefficients A and B in laser?
6. What is the principle of laser?
7. What are the conditions needed for the laser action?
8. What is meant by population inversion and metastable state.?
9. What is meant by pumping mechanism?
10. What are different types of pumping mechanism to achieve population inversion?
11. What are the important requisites for laser action to takes place?
12. What are the different types of laser?
13. What is meant by direct band gap and indirect band gap semiconductor?
14. What are the roles played by the He and N2 in CO2 laser?
15. Mention any two applications of laser.
16. What is meant by hologram?
17. What is the reason for using a laser beam in holography?
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State any four applications of laser in engineering and industry.
State any four application of laser in medicine.
How will you convert LED into laser source?
Compare holography with photography.
Write down the ratio of the stimulated emission to spontaneous emission.
What is the principle of semiconductor laser?
What are the advantages of heterojunction semiconductor laser over homojunction semiconductor laser?
Part – B
1. For atomic transitions, derive Einstein relation and hence deduce the expressions for the ratio of spontaneous
emission rate to the stimulated emission rate. (16)
2. Explain the different methods used for pumping of atoms.(8)
3. What is a gas laser? Explain the working of He-Ne laser with relevant diagram.(8)
4. Describe the construction and working of Nd-YAG laser.(8)
5. What is a molecular gas laser? Explain the modes of vibrations of CO 2 molecule and describe the construction and
working of a CO2 laser with a neat sketch. (16)
6. What is a semiconductor diode laser? Explain the construction and working of Ga-As laser. (homojunction semiconductor
laser)(8)
7. Explain with a neat sketch the construction and reconstruction of a hologram using laser beam.(8)
8. Write a short notes on material processing?(8)
Unit 3 FIBRE OPTICS
Part – A
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What is fiber optics?
Define acceptance angle.
Define numerical aperture.
What are the types of optical fibers?
Differentiate single mode from multimode fiber.
Mention the applications of optical fibers as sensors.
Define total internal reflection.
What are the conditions to obtain total internal reflection?
Mention the components involved in fiber optical communication system.
What are the advantages of the fiber optical communication system over conventional system?
What is the basic principle of fiber sensors?
Why optical fibers are called as waveguides?
What are the differences between step index and graded index fiber?
What type of sources is used for optical communication system?
Define intermodal dispersion.
What is meant by attenuation?
What is intrinsic absorption?
What is dispersion?
Calculate the numerical aperture and acceptance angle of a fibre with the core index of 1.54 and cladding 1.50.
What is the role of cladding in an optical fibre?
What is splicing? Mention the two types of splicing.
List four factors that cause loss in optical fibre.
What is an Endoscopes? Mention its use.
A silica optical fiber has a core refractive index of 1.5 and cladding refractive index of 1.47. calculate the critical angle at the
core-cladding interface.
25. What are the types of sensors used in fiber optic communication?
26. Find the numerical aperture and acceptance angle of an optical fiber whose core has a refractive index of 1.5 (refractive index
of cladding = 1.447 and refractive index of air =1)
27. What are active and passive sensors?
Part – B
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2.
Define numerical aperture and derive expression for the numerical aperture and acceptance angle of fibre in terms of
refractive index of the core and cladding of the fibre. (16)
What are the different types of fibre optic sensors? Explain the working of any two sensors.
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4.
Describe the construction and working of an Endoscope.
Explain in detail about sources and detectors involved in optical fibre communication with necessary diagram. (16)
5.
Explain fibre optical communication system with neat block diagram.(8)
6.
(a) Discuss in detail the classification of optical fibres based on mode and refractive index.
(b) Explain the fibre optic temperature sensor with neat diagram.
7.
(i) Describe a fiber optic communication system.
(ii) Describe the principle, construction and working of light emitting diode.
(iii) State the advantages of light emitting diodes in electronic display. (6+8+2)
Unit 4 Quantum Physics
Part – A
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What is the physical significance of wave function?
Give the special features of Quantum theory of radiation.
What is the principle of electron microscope?
Explain the principle of transmission electron microscope
Calculate the de-broglie wavelength of an electron, which has been accelerated from rest on application of potential of 400V
Deduce Rayleigh-Jeans law from Planck’s law for radiation.
The wavelength of X-ray photon is doubled when it is scattered through an angle of 900 by a target material. Find the incident
wavelength.
8. The de-broglie wavelength of an electron is 1.226A0. What is the accelerating potential?
9. What is Compton wavelength and calculate its value.
10. What are degenerate and non degenerate states?
Part – B
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What are the basic postulates of quantum theory of light? Derive Planck’s law of radiation. (4+12)
Derive time dependent Schrodinger wave equation and hence derive time independent Schrodinger wave equation.
(16)
Give the theory of Compton effect and briefly explain its experimental verification. (16)
(i) Derive time-independent Schrodinger wave equation. (6)
(ii)Using time-independent Schrodinger wave equation normalize the wave function of electron trapped in a Onedimensional potential well. (10)
Compare SEM and TEM.(6)
An X ray photon of wavelength 1.24 x 10 -3A0 is scattered by a free electron through an angle 90 0. Calculate the energy of the
scattered photon(4)
With a neat sketch, describe the scanning process of a SEM.
Unit 5 Crystal Physics
Part – A
1. Define space lattice.
2. What is meant by basis?
3. Define the term crystal structure.
4. What are interfacial angles?
5. Define the term unit cell.
6. What is meant by lattice parameters?
7. Name the seven types of crystal systems.
8. What is Bravais lattice?
9. What are miller indices?
10. Draw the crystal planes for (110) and (001).
11. Define the following term (i) Atomic radius (ii) Co ordination number (iii) packing density
12. Show that for a BCC crystal structure, the lattice constant is given by
, where r is the atomic radius.
13. Establish the relationship between the radius and the inter atomic distance for a FCC crystal.
14. Draw a diagram of the unit cell of the closed HCP.
15. For a cubic lattice, draw the (231) plane showing the value of intercepts with the coordinate axes.
16. Draw the schematic diagram of SC, BCC and FCC unit cells.
17. What is a primitive unit cell?
18. Show that for a simple cubic system d100:d110:d111: :
6:
3:
2
19. The lattice constant for a unit cell is 2.02Å. Calculate the spacing of (111) plane.
20. The lattice constant for a FCC structure is 4.938A0. Calculate the interplanar spacing of (220) planes.
21. The lattice constant of a metal with cubic lattice is 2.88 A0. The density of metal is 7200 Kg/m3. Calculate the number of unit
cell present in 1Kg of the metal.
22. Determine the lattice constant for FCC crystal having atomic radius 1.476A0.
23. Which crystal structure is having least coordination number? Give example.
24. Give the relationship between interplanar distance and cubic edges.
25. What is polymorphism and allotropy?
26. Give an account on imperfections in crystal.
27. Write a note on point imperfections.
28. What are Vacancies?
29. Write a note on grain boundaries.
30. Write a short note on Burger vector?
31. What are dislocations?
32. What are Frenkel and Schottky imperfections?
Part – B
1.
What are miller indices? How will you determine the miller indices of a given plane? What are the distinct features of miller
indices?
2. Define the term coordination number, atomic radius and packing density. Calculate the above factors for SC, BCC
and FCC.
3. Determine the coordination number and packing density for HCP structure. Show that a HCP structure demands an
axial ratio of 1.6333.
4. Explain in detail the crystal defects and their types
5. Explain the characteristics of unit cell of the diamond and NaCl structure.
6. What is packing factor? Obtain packing factors for SC, BCC and FCC structures. (16)
7. What are miller indices? Derive an expression for interplanar spacing for (hkl) planes of a cubic structure. (4+12)
8. Calculate the lattice constant and distance between two adjacent atoms for potassium bromide crystal (FCC lattice) having
the density and molecular weight of 2700 Kg/m3 and 119 resp.(6)
9. Show that the face centered cubic and hexagonal close packed structure has the same atomic packing factor. (10)
10. Show that for the cubic structure the interplanar distance d in terms of miller indices and cell edge a is given by
(8)
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(i) What are Bravais lattice?
(ii) Derive an expression for the interplanar spacing in a cubic structure.
(iii) With a neat diagram describe the edge dislocation. (2+8+6)