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Tuesday, 20 November 2012

Solid state physics-Model question paper for MSc/PhD

1(a) Outline Bohr’s theory of hydrogen atom and derive an expression for the radius of the first Bohr orbit for the normal hydrogen atom. (6 Marks)
(b) What are ionic crystals? Explain the formation of an ionic crystal and obtain an expression for its cohesive energy. (6 Marks)
(c) Calculate the potential energy of the system of Na+ and Cl- ions when they are 0.2 nm apart. (4 Marks)
(d) The atomic weights and densities of aluminium and copper are 26.98 and 63.54 and 2700 kg/m3 and 8960 kg/m3 respectively. Calculate the number of atoms present in unit volume of aluminium and copper. (4 Marks)
2(a) Write a note on various symmetry operations present in a crystal. (4 Marks)
(b) What are Miller indices? Illustrate with examples. Draw (112) and (232) planes. (6 Marks)
(c) Explain with neat sketches the different imperfections in a crystal. (6 Marks)
(d) The fraction of vacancy sites in a metal is 10-10 at 5000C. What will be the fraction of vacancy sires at 10000C.? (4 Marks)
3(a) Discuss a method of investigating the structure of a single crystal using X-rays. (6 Marks)
(b) Write a note on relaxation time. (4 marks)
(c) Explain quantum mechanical tunneling in solids and its significance. (6 Marks)
(d) A copper wire whose diameter is 0.16 cm carries a steady current of 10 amp. What is the current density in the wire? Also calculate the drift velocity of the electrons in copper. (4 Marks)
4(a) Discuss salient features of Debye’s theory of specific heat of solids. (4 Marks)
(b) Discuss the domain structure in ferromagnetic materials. Explain the reasons for the strong ferromagnetic property found in iron, cobalt and nickel. (6 Marks)
(c) Discuss Langevin’s theory for a paramagnetic gas and obtain an expression for the paramagnetic susceptibility of the gas. What are the main drawbacks of this theory? (6 Marks)
(d) Compute Debye temperature for diamond whose atomic weight and Young’s modulus are 12 and 1012 Nm2 respectively. Density of diamond is 3500 kg/m3. (4 Marks)
5(a) Derive the London equations and explain the term coherent length. Explain 1-2-3 superconductors. (6 Marks)
(b) Discuss d.c and a.c Josephson effect and explain their importance. (6 Marks)
(c) Explain the properties of Cooper pairs. (4 Marks)
(d) The London penetration depths for Pb at 3K and 7.1K are respectively 39.6nm and 173 nm. Calculate its transition temperature as well penetration depth at 0K. (4 Marks)
6(a) Distinguish between Zener breakdown and avalanche breakdown. (4 Marks)
(b) Derive an expression for the density of holes in an intrinsic semiconductor. Suggest a method for evaluating the energy gap of the semiconductor. (6 Maks)
(c) Discuss the physical origin and uses of Hall effect. (6 Marks)
(d) The room temperature electron mobility in GaAs is 0.08 m2V-1S-1. Calculate the diffusion constant of electrons. (4 Marks)
7(a) What is meant by dielectric loss? State its importance. (4 Marks)
(b) How does dielectric constant of a solid containing permanent dipole vary with temperature? Illustrate your answer with an example. (6 Marks)
(c) Discuss the salient features of optical absorption in the case of metals, semiconductors and insulators. (6 Marks)
(d) A fiber optic link is operated at a wavelength of 1.3 mm. Find the maximum bit-rate of a 25 km line made from a multimodal step-index fiber. Given n1=1.46 and n2=1.46. (4 Marks)
8(a) Write notes on gaseous insulating materials and liquid insulating materials. (6 Marks)
(b) Differentiate between thermosetting resins and thermoplastic resins. (6 Marks)
(c) Write a note on laminated composites. (4 Marks)
(d) Calculate the Young’s modulus of a composite with glass fibers reinforced in phenol formaldehyde plastics. The volume fraction of plastics is 33.3%. The modulus of glass fiber is 6.9×104 MPa and that of polymers 6.9×102 MPa.  (4 Marks)

Thursday, 15 November 2012

Optical fiber communications-model question paper for B.E/B.Tech/M.E/M.Tech/MSc

1(a) Write a note on linear, elliptical and circular polarization. (6 Marks)
(b) Differentiate between step index fiber and graded index fiber. (4 Marks)
(c) Explain vapour-phase axial deposition method of optic fiber fabrication. (6 Marks)
(d) A signal passes through three cascaded amplifiers, each of which has a 5 dB gain. What is the total gain in dB? By what numerical factor is the signal amplified? (4 Marks)
2(a) Write notes on modal delay and group delay. (6 Marks)
(b) What is material dispersion? Explain. (6 Marks)
(c) Define external quantum efficiency. (4 Marks)
(d) An optical fiber 40 km long has a loss of 0.4 dB/km. What is the minimum input power to maintain an optical power of 2mW at the receiving end? (4 Marks)
3(a) Explain different lensing schemes for coupling improvement. (6 Marks)
(b) What is connector return loss? Explain. (4 Marks)
(c) Explain the construction and working of Avalanche photodiode. (6 Marks)
(d) Quantum efficiency of a silicon avalanche photodiode is 65% at a wavelength 900 nm. If an optical power of 0.5 mW produces a multiplied photocurrent of 10mA, determine the multiplication. (4 Marks)
4(a) Explain the working of high impedance amplifier and transimpedance amplifier. (6 Marks)
(b) What is an eye diagram? Explain. (4 Marks)
(c) Write notes on homodyne detection and heterodyne detection. (6 Marks)
(d) If a bit-corrupting noise burst lasts for 2ms, how many bits are affected at data rates of 10 Mb/s, 100 Mb/s and 2.5 Gb/s? (4 Marks)
5(a) What is extinction ratio penalty? Explain. (4 Marks)
(b) Explain the term ‘Chirping’. (4 Marks)
(c) Explain multichannel amplitude modulation and multichannel frequency modulation. (6 Marks)
(d) Calculate the optical modulation index of a laser for frequency division multiplexing of 60 FM signals. 30 of these signals have a per channel modulation index 3% and remaining 30 signals have per channel modulation index 4%. (6 Marks)
6(a) What is wavelength division multiplexing? Explain the operational principles. (8 Marks)
(b) Differentiate between a 2×2 fiber coupler and 2×2 waveguide coupler. (8 Marks)
(c) A DWDM optical transmission system is designed to have 100 GHz channel spacings. How many wavelength channels can be utilized in the 1536 to 1556 nm spectral band? (4 Marks)
7(a) Explain the construction and working of Erbium doped fiber amplifier, EDFA. (6 Marks)
(b) Explain the significance of Raman scattering in the design of Raman fiber amplifiers. (4 Marks)
(c) What is stimulated Brillouin scattering? Explain. (6 Marks)
(d) A single mode fiber has an attenuation of 0.55 dB/km at 1310 nm and 0.28 dB/km at 1550 nm. Compare the effective lengths of this fiber at 1310 nm and 1550 nm. (4 Marks)
8(a) Explain different network topologies with neat sketches. (8 Marks)
(b) Explain the terms optical packet switching and optical burst switching. (4 Marks)
(c) Explain the three layers of optical performance monitoring. (4 Marks)
(d) Show that when using an OTDR, an optical pulse width of 5 ns or less is required to locate a fiber fault to within ± 0.5 m of its true position. (4 Marks)

Tuesday, 6 November 2012

Computer integrated manufacturing-Model question paper for B.E/B.Tech

1(a) What is the difference between CIM I and CIM II? (5 Marks)
(b) A manufacturing based economy is superior to a service-based economy. Write your comments on this statement. (5 Marks)
(c) Explain the difference between odd and even parity systems. (6 Marks)
(d) Convert &H6C into binary form. (4 Marks)
2(a) Write a note on limitation of the BCD code and attraction of Gray code. (8Marks)
(b) Mention the advantages of fiber optic cabling. (6 Marks)
(c) A communication line operates at a signal-to noise ratio of 25 dB and a bandwidth of 4000Hz. What is the maximum speed at which data transfer is possible on this line? (6 Marks)
3(a) Discuss the reasons behind the need of database for a manufacturing company. (6 Marks)
(b) How does DBMS software differ from file manager software? (6 Marks)
(c) What is reverse engineering and when is it practiced? (4 Marks)
(d) What is the Rule of Ten? What is its message? (4 Marks)
4(a) Compare C-posts with G-posts. (6 Marks)
(b) Discuss the difficulties that may arise when product designers are entrusted with the task of developing part programs. (4 Marks)
(c) What is the role of FMS in CIM? (4 Marks)
(d) Describe the production method of a pair of scissors. Explain all the basic processes involved. (6 Marks)
5(a) Discuss the role of PLCs in CIM plants. (4 Marks)
(b) Discuss the major problems in integrating industrial robots with another flexible automation system of a modern plant such as AGV. (8 Marks)
(c) Discuss the role of AS/RS in streamlining material handling. How do they contribute to integration at the shop floor. (8 Marks)
6(a) What is SPC and how does it help in achieving the objectives of CIM? (8 Marks)
(b) Name two individuals who have made extraordinary contributions to the advancement of quality in last 30 years. Mention their contributions. (6 Marks)
(c) If the specification limits for the strip thickness of delicate strip are 8.96 and 9.44mm, find the values of PCR and Cpk and comment on them. Discard the out-of-control points before assessing the process capability. (6 Marks)
7(a) Explain the meaning of expert systems. How do they differ from conventional software? (6 Marks)
(b) Write a note on Dr.Aaron's views on modern manufacturing wisdom. (5 Marks)
(c) Write an outline for a CIM course. (4 Marks)
(d) Write job specifications for a CIM technician and CIM engineer. (5 Marks)
8(a) Write a note on use of laser in manufacturing. (4 Marks)
(b) What is meant by multimedia? Discuss how it can help CIM. (6 Marks)
(c) Mention the difficulties companies experience while implementing CIM face. (6 Marks)
(d) Write your comments on the statement, 'Taylorism is compatible with CIM'. (4 Marks)

Saturday, 3 November 2012

Engineering Economics-Model question paper for B.E/B.Tech

1(a) Why do economic projections for a future event tend to vary more widely than engineering estimates for performance for a new design? (4 Marks)
(b) Write a note on time-value equivalence. (6 Marks)
(c) Differentiate between simple interest and compound interest with examples. (6 Marks)
(d) A loan of $200 is made for a period of 13 months, from January 1 to January 31 the following year, at a simple interest rate of 10%.  What future amount is due at the end of the loan period? (4 Marks)
2(a) Write notes on valuation and future worth. (6 Marks)
(b) What is equivalent annual cost? Explain. (4 Marks)
(c) Explain the term perpetual life. (4 Marks)
(d) The lease on a commercial complex amounts to $10000 per month for 10 years. If payments are made on the first of each month, what is the present worth of the agreement at a nominal annual interest rate of 14%, compounded monthly? (6 Marks)
3(a) Explain the method of calculation of internal rate of return. (6 Marks)
(b) Write a note on classification of alternatives. (5 Marks)
(c) Write a note on obsolescence forced by competition. (4 Marks)
(d) A $5000 bond matures in 10 years and pays 2.5% interest twice a year. If the bond sold for $5050, what is the actual investment rate? (5 Marks)
4(a) Mention some importance irregularities in benefit/cost comparisons. Explain in detail. (10 Marks)
(b) Explain the method of dettermination of simulation in fighter pilot training. (6 Marks)
(c) A public good has a linear demand function such that the first unit available is valued at $100000, but when 50000 units are available, the per-unit value drops to $2. What is consumer's surplus when the demand is 30000 units? (4 Marks)
5(a) Explain straight line method of computing depreciation charges. (6 Marks)
(b) Write a short note on MACRS depreciable property. (6 Marks)
(c) What is effective income tax?(4 Marks)
(d) An asset with a tax life of 5 years was purchased 3 years ago at a cost of $10000. It now has a book value of $5000 based on MACRS straight line depreciation. If it is sold for $1000, what is its expected tax life? (4 Marks)
6(a) Explain the impact of inflation on economic valuations and stock market. (8 Marks)
(b) What are the different types of leases? (4 Marks)
(c) What is single parameter sensitivity? (4 Marks)
(d) An asset can be purchased for $80000 and will have a 10-year useful life. A suggested lease arrangement is to pay rental charges of $28000 for the first 4 years and then make annual payments of $1500 for the remaining 6 years. evaluate the suggestion. (4 marks)
7(a) Mention the basic concepts in break-even analysis. (8 Marks)
(b) What is dumping? (4 Marks)
(c) Define expected value. (4 Marks)
(d) What are acceptable investment diagrams. explain. (4 Marks)
8(a) Explain Monte Carlo simulation. (6 Marks)
(b) What is Bayesian analysis. Explain. (5Marks)
(c) Explain the procedures involved in attribute weighting. (5 Marks)
(d) Explain attribute value assessment. (4 Marks)