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MEHRAN UNIVERSITY OF ENGINEERING AND TECHNOLOGY,JAMSHORO.

FIRST TERM FIRST YEAR (1ST TERM) B.E.(CIVIL) FOR 05-BATCH REGULAR

EXAMINATION 2005 UNDER EXTERNAL SYSTEM.

Dated: 21-05-2005. Time Allowed: 03 Hours. Max.Marks-80.

NOTE: ATTEMPT ANY FIVE QUESTIONS.SELECTING AT LEAST TWO QUESTIONSFROM

EACH SECTION. ALL QUESTIONS CARRY EQUAL MARKS.

Q.No. SECTION-I

1. (a) What is adiabatic process and derive an expression for the work done during adiabatic process.

[06]

(b) A system contains 0.2 m3 of a gas at a pressure of 3.5 bar and 150 C. it is expanded adiabatically

till the pressure falls to 1 bar. The gas is then heated at a constant pressure till its enthalpyincreases by 70 KJ. Determine the total work done. Take Cp =1 and Cv= .714) [10]

2. (a) What do you understand by IC engine? Describe its main components. [04]

(b) Compare and contrast Diesel engine with petrol engine. [04]

(c) What is an air compressor? Describe some uses of compressed air. [04]

(d) With reference to reciprocating air compressor explain (i) Single acting compressor (ii) Double

acting compressor (iii) Single stage compressor (iv) Double stage compressor. [04]

3. (a) Draw the PV and TS diagrams for Otto Cycle. What is practical application of Otto cycle? [05]

(b) Draw the PV and TS diagrams for Diesel Cycle. What is compression ignition engine? [05]

(c) What is compression ratio? There are two petrol engines A and B with compression ratios of

2 and 4 respectively. Calculate their air standard efficiencies and tell how does efficiency of

petrol engine is related with compression ratio. [06]

4. (a) State and explain second law of thermodynamics. [06]

(b) What is dryness fraction? Describe different types of steam. [05]

(c) What is thermodynamic system? What do you understand by open, closed and isolatedsystems? [05]

SECTION-II

5. (a) Define the active and passive circuit element and ohms law.

(b) Three resistors 4, 6 and 12 ohms are connected in parallel. If supply voltage is 120 volts then find(i) Current flowing in each resistor.

(ii) Total power observed by the circuit.

6. (a) Explain briefly the working principle and construction of transformer

(b) Drive the emf equation of transformer

7. What is PN-junction diode ? Draw and explain working of half wave and full wave rectification.

8. Write the short notes any three of the following

(a) Faradays Laws of electromagnetic induction

(b) Kirchhoffs laws

BASIC ELECTRO MECHANICAL ENGINEERING

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(c) Charging and discharging of capacitor process

(d) Magnetic flux density

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