Feb. 2008 Question Paper with Model Answer

BE (First/Second) Semester Exam

(Common to all Branches)

Time: 3 hrs

Maximum Marks: 100

Minimum Marks: 35

Note: Attempt FIVE questions, selecting ONE questions from each unit. Suitably assume any missing data. All questions carry equal marks.

Unit-I

1. a) Draw a neat sketch of iron–carbon equilibrium diagram and explain the following: (i) Eutectic reaction (ii) Eutectoid reaction (iii) Peritectic reaction 10 marks

Ans: Refer Page 7-9 of BME - Basant Agrawal, Wiley India
1. b) Give the composition, properties and uses of mild steel (low carbon) and high-carbon steels. 10 marks
Ans: Refer Page 4 of BME - Basant Agrawal, Wiley India

Or

2. Write short notes on the following: (i) Cast iron (ii) Carbon steels (iii) Alloy steels (iv) Classification of engineering materials 5 marks each

Ans: Refer Page 1-7 of BME - Basant Agrawal, Wiley India

Unit-II

3. Explain the construction, working and uses of the following: (i) Venturimeter (ii) Rotameter (iii) Prony brake dynamometer (iv) Vernier calliper 5 marks each

Ans: Refer Page 58, 59, 69 and 79 of BME - Basant Agrawal, Wiley India

Or

4. (a) Explain the principle of temperature measurement. 5 marks

Ans: Refer Page 39 of BME - Basant Agrawal, Wiley India
4. (b) Explain the working of a thermocouple (thermoelectric) and radiation pyrometer with neat sketches. 10 marks

Ans: Refer Page 43 and 44 of BME - Basant Agrawal, Wiley India

4.(c) Explain the working of a Bordon pressure gauge with a neat sketch. 10 marks

Ans: Refer Page 48-49 of BME - Basant Agrawal, Wiley India

Unit-III

5. (a) How turbines are classified? Explain. 10 marks

Ans: Refer Page 149 of BME - Basant Agrawal, Wiley India
5. (b) A pipe of 200 m has a slope of 1 in 100 and tapers from 1 m diameter at the high end to 0.4 m at the low end. Rate of water fl ow is 4000 l/min. If the pressure at the high end is 50 kPa, find the pressure at the low end. 10 marks

Ans: 69.84 kPa, Refer Page 129 of BME - Basant Agrawal, Wiley India for detail solution

Or

6. Describe the construction and working principle of (i) Pelton wheel (ii) Kaplan turbine 10 marks each

Ans: Refer Page 150, 151 of BME - Basant Agrawal, Wiley India

Unit-IV

7. (a) State and explain First law of thermodynamics. 10 marks

Ans: Refer Page 165-167 of BME - Basant Agrawal, Wiley India
7. (b) What short notes on the following: (i) Boiler classification (ii) Eco-friendly refrigerants. 10 marks

Ans: Refer Page 216, 269 of BME - Basant Agrawal, Wiley India

Or

8.(a) Describe the classification, construction and working of a Cochran boiler. 10 marks

Ans: Refer Page 219-221 of BME - Basant Agrawal, Wiley India

8.(b) Explain vapour absorption system with a neat sketch. 10 marks
Ans: Refer Page 266-267 of BME - Basant Agrawal, Wiley India

Unit -V

9. (a) Explain the working of a two-stroke petrol engine. 10 marks

Ans: Refer Page 331-332 of BME - Basant Agrawal, Wiley India
9. (b) Explain Otto cycle and derive an expression for efficiency of Otto cycle. 10 marks

Ans: Refer Page 306-307 of BME - Basant Agrawal, Wiley India

Or

10. Explain the working of a four-stroke diesel engine. 10 marks

Ans: Refer Page 330-331 of BME - Basant Agrawal, Wiley India

10. (b) In an air standard diesel cycle with compression ratio 14, the conditions of air at the start of compression stroke are 1 bar and 300 K. After addition of heat at constant pressure, the temperature rises to 2774 K. Determine the thermal efficiency of the cycle, net work done per kg of air and the mean effective pressure. 10 marks

Ans: 53.68%, 1031.42 kJ/kg, 12.9 bar

Refer Page 319-321 of BME - Basant Agrawal, Wiley India for detail solution