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C14–EE–301/C14–CHPP–301/C14–PET–301

BOARD DIPLOMA EXAMINATION, (C–14)

OCT/NOV—2015

DEEE—THIRD SEMESTER EXAMINATION

ENGINEERING MATHEMATICS—II

Time : 3 hours ] [ Total Marks : 80

PART—A 3×10=30

Instructions : (1) Answer all questions.

(2) Each question carries three marks.

(3) Answers should be brief and straight to the point

and shall not exceed five simple sentences.

1. Evaluate : (3x 3 4x2 5x 7)dx

2. Evaluate :

3. Evaluate :

1

dx

16x2 9

m tan1 x

e

4. Evaluate :

2

dx 1 x2

x2 e 2xdx

* 0

* 2 [ Contd...

the

2

5. Find* mean value of f (x)

1

1 x2

in (0, 1).

6. Form the differential equation for y A cos3x B sin 3x, where

A and B are arbitrary constants.

7. Solve : dy

dx

8. Solve :

(x2 2xy)dx (sin y x2)dy 0

9. List the measures of dispersion and find the range of the following

data :

60, 50, 85, 90, 70, 40, 110, 130, 120, 100

10. What is correlation coefficient? Write the formula of Karl Pearson

correlation coefficient for two variables X and Y and mention two

of its properties.

PART—B 10×5=50

Instructions : (1) Answer any five questions.

(2) Each question carries ten marks.

(3) Answers should be comprehensive and the criterion

for valuation is the content but not the length of the

answer.

11. (a) Evaluate : cos4x cos2x dx

(b) Evaluate :

*

dx

3x 2x 5

1 y2

1 x2

* 3 [ Contd...

1

12. (a) E*valuate :

sin3 cos10 d

(b) Evaluate :

x tan1 x dx

13. (a) Evaluate :

dx 13 12 cos x

(b) Evaluate :

/2

0

sinn x

dx cosn x sinn x

14. (a) Evaluate : 1

3 x log dx

1 3 x

(b) Find the area bounded by the curve y x2 8x 15 and

X-axis.

15. (a) Find the volume of the paraboloid generated by revolving the

parabola y2 4ax about X-axis from x 0 to x h.

(b) Obtain the value of dx

using the Simpson’s 1/3rd rule

01 x2

by dividing the interval (0, 1) into four equal parts.

16. Solve : x2y dx (x2 y 3)dy 0

17. (a) Solve :

dy 3x2y x2

dx

(b) Solve :

dy

* dx

xy xy 3

18. (a) T*he goals scored by two teams A and B in a football season are

as follows :

Number of goals

scored in match

Number of matches

Team A Team B

0 27 17

1 9 9

2 8 6

3 5 5

4 4 3

Find the team which is more consistent from the above

data.

(b) Two judges in a beauty competition rank the 12 entries as

follows :

x 1 2 3 4 5 6 7 8 9 10 11 12

y 12 9 6 10 3 5 4 7 8 2 11 1

Find the degree of agreement between the two judges.

$ $ $

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C14–EE–302

BOARD DIPLOMA EXAMINATION, (C–14)

OCT/NOV—2015

DEEE—THIRD SEMESTER EXAMINATION

DC MACHINES

Time : 3 hours ] [ Total Marks : 80

PART—A 3×10=30

Instructions : (1) Answer all questions.

(2) Each question carries three marks.

(3) Answer should be brief and straight to the point

and shall not exceed five simple sentences.

1. Explain the working principle of DC generator.

2. State the Fleming’s right hand rule.

3. Classify DC generators based on excitation.

4. State the methods to improve commutation.

5. Define critical resistance and critical speed. 1½+1½

6. State the working principle of DC motor.

7. Derive the torque equation of a DC motor.

* 8. What is the necessity of starter for DC motor?

* 2 [ Contd...

9. List t*he methods of speed control of DC motors.

10. List the various methods of motor testing.

PART—B 10×5=50

Instructions : (1) Answer any five questions.

(2) Each question carries ten marks.

(3) Answers should be comprehensive and the criterion

for valuation is the content but not the length of the

answer.

11. (a) Derive the EMF equation of a DC generator. 5

(b) A shunt generator delivers 450A at 230V and the resistance

of the shunt field and armature of 50 and 0 03

respectively. Calculate the generated EMF. Neglect brush

drop. 5

12. (a) Derive the condition for maximum efficiency of a DC

generator. 4

(b) A 10kW, 250V DC shunt generator has total rotational

losses of 600W. Its armature and shunt field resistance are

0 5 and 125 respectively. Calculate the efficiency at

rated load. 6

13. Derive the equation for demagnetizing (ATd) and

crossmagnetizing (ATc) ampere turns per pole. 5+5

14. (a) State the conditions for parallel operations of DC

generators. 5

(b) Explain OCC, internal and external characteristics of DC

shunt generator. 5

15. (a) Explain the significance of back EMF and write its formula. 5

* (b) Explain the power stages in a DC motor. 5

16. (a) D*raw the electrical and mechanical characteristics of DC

series motor. 6

(b) List the applications of DC motor. 4

17. Explain the working of 3 point starter with neat sketch. 10

18. Draw the circuit diagram to perform a brake test on DC shunt

motor and explain. 10

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C14–EE–303

BOARD DIPLOMA EXAMINATION, (C–14)

OCT/NOV—2015

DEEE—THIRD SEMESTER EXAMINATION

ELECTRICAL CIRCUITS

Time : 3 hours ] [ Total Marks : 80

PART—A 3×10=30

Instructions : (1) Answer all questions.

(2) Each question carries three marks.

(3) Answer should be brief and straight to the point and

shall not exceed five simple sentences.

1. Define active and passive circuits. 1½+1½=3

2. State Kirchhoff’s laws. 1½+1½=3

3. Define the following terms : 1+1+1=3

(a) Cycle

(b) Time period

(c) Amplitude

4. Define phase and phase difference of an alternating quantity.

1½+1½=3

5. Convert the following rectangular to polar or polar to

rectangular : 1½+1½=3

(a) 3 – j 6

* (b) 10045

* 2 [ Contd...

6. Deriv*e the relation between voltage and current in a pure

inductive circuit. 3

7. When a voltage of (100+ j 60) V is applied to a circuit, a current

of (3+ j 6) A is flowing. Find the average power consumed in the circuit. 3

8. Compare series and parallel resonant circuits in any three

aspects. 3

9. What are the basic features of a balanced 3 system? 3

10. List out any three advantages of poly-phase system over single-

phase system. 3

PART—B 20×2=40

Instructions : (1) Answer any five questions.

(2) Each question carries ten marks.

(3) Answers should be comprehensive and the criterion

for valuation is the content but not the length of the

answer.

11. (a) Derive an equation for transformation of star-connected

resistances into delta-connected resistances. 5

(b) A network of resistors is shown in Fig. 1. Find the

resistance between the terminals A and B by using

star/delta transformation. 5

* Fig. 1

* 3 [ Contd...

12. Find*the current through 4 resistor of the circuit shown in

Fig. 2 by using Kirchhoff’s laws. Also find the total current

supplied by the voltage source. 8+2

Fig. 2

13. (a) Convert the given current source (Fig. 3) into voltage

source. 3

Fig. 3

(b) Find the current through 12 ohm resistor for the circuit

shown in Fig. 4 by using superposition theorem. 8

Fig. 4

14. (a) Derive the formula for average value of sinusoidal current

wave by using analytical method. 4

(b) A sinusoidal current wave is given by i 100 sin100 t.

Determine (i) the average value (ii) RMS value (iii) form * factor (iv) peak factor. 2+2+1+1

15. (a) D*erive the relation between voltage and current in a pure

capacitive circuit. 4

(b) A coil takes a current of 5 A from a 20 V d.c. supply. When

connected to a 200 V, 50 Hz a.c. supply, the current is

25 A. Calculate (i) resistance (ii) inductance (iii) impedance

of the coil, and power factor of the circuit. Also draw the relevant phasor diagram. 4+2

16. (a) Define resonant frequency and derive the formula for

resonant frequency of an RLC series. 4

(b) Find total impedance, line current, voltage across each

and power factor for a series circuit, consisting of a coil

of inductance 0·1 H, resistance 8 and a capacitance of

120 F connected to a 250 V, 50 Hz supply.

6

17. (a) An inductive coil of resistance 20 ohms and inductance

0·01 H is connected to a 200 V, 50 Hz supply. What

capacitance placed in parallel will produce resonance? Also

find the total current taken from the supply.

4

(b) A coil of resistance 50 and inductance 318 mH is

connected in parallel with a circuit consisting of a 75

resistor in series with a 159 F capacitor. The circuit is

connected to a 230 V, 50 Hz supply. Determine the supply

current and power factor of the circuit. 6

18. (a) Define polyphase circuit. Draw graphically 3-phase

waveforms and write their e.m.f. equations induced in three

phases. 5

(b) Three similar coils each having an impedance of

(8 j 6) ohm are connected in star to a 3-ph 400 V supply.

Find the line current, power and power factor. If two

wattmeters are used to measure power, calculate the

reading of two wattmeters. 5

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C14–EE–305

BOARD DIPLOMA EXAMINATION, (C–14)

OCT/NOV—2015

DEEE—THIRD SEMESTER EXAMINATION

ELECTRONICS—I

Time : 3 hours ] [ Total Marks : 80

PART—A 3×10=30

Instructions : (1) Answer all questions.

(2) Each question carries three marks.

(3) Answer should be brief and straight to the point

and shall not exceed five simple sentences.

1. Define (a) Capacitance (b) Inductance (c) Resistance.

2. List the losses in inductor.

3. Distinguish between intrinsic and extrinsic semiconductors.

4. Draw the circuit of full wave rectifier.

5. Compare centre tapped and bridge type full wave rectifier.

6. Draw the symbols of LED, UJT, SCR.

7. List the application of solar cell.

* 8. What is the necessity of transistor biasing?

* 2 [ Contd...

*

9. What is meant by faithful amplification?

10. List the applications of RC coupled amplifier.

PART—B 10×5=50

Instructions : (1) Answer any five questions.

(2) Each question carries ten marks.

(3) Answers should be comprehensive and the criterion

for valuation is the content but not the length of the

answer.

11. (a) What are the factors affecting the value of capacitance? 5

(b) Explain the specifications of resistors. 5

12. Explain the working of PN diode in (a) Forward bias and

(b) Reverse bias. 5+5

13. (a) State the need of a filter. 4

*

(b) Explain the working of Zener diode as a voltage regulator. 6

14. (a)

Give four differences between LED and LCD.

4

(b) Explain the working of photo-diode. 6

15. (a)

List four applications of photo-transistor.

4

(b) Explain the working of photo cell. 6

16. Expla*in potential divider bias method.

17. (a) Classify amplifier based on period of conduction, frequency

and function. 6

(b) Compare different types of coupled amplifier. 4

18. Explain working of transformer coupled amplifier and draw its

frequency response. 10

$ $ $

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C14–EE–306

BOARD DIPLOMA EXAMINATION, (C–14)

OCT/NOV—2015

DEEE—THIRD SEMESTER EXAMINATION

GENERAL MECHANICAL ENGINEERING

Time : 3 hours ] [ Total Marks : 80

PART—A 3×10=30

Instructions : (1) Answer all questions.

(2) Each question carries three marks.

(3) Answers should be brief and straight to the point

and shall not exceed five simple sentences.

1. Define the terms linear strain and lateral strain.

2. A steel rod of 20 mm diameter and 600 mm long is subjected to an

axial pull of 40 kN. Determine the elongation of the rod if

E 2 105 N / mm2.

3. Write the formula for polar moment of inertia for solid shaft and

hollow shaft.

4. (a) Define torsion.

(b) Which stress is induced in shaft, when it is subjected to the

twisting moment?

* 5. Define the terms clearance volume and swept volume.

* 2 [ Contd...

6. List o*ut any six major components of IC engine.

7. Write the classification of boilers.

8. State the need of (a) pressure gauge and (b) stop value.

9. How are the impellers arranged to produce high head and to deliver

high discharge in centrifugal pump?

10. Write the advantages and disadvantages of anti-friction bearings.

PART—B 10×5=50

Instructions : (1) Answer any five questions.

(2) Each question carries ten marks.

(3) Answer should be comprehensive and the criterion

for valuation is the content but not the length of the

answer.

11. A steel bar 350 mm long is 20 mm in diameter for 200 mm of

length and 15 mm diameter for the remainder. If a tensile load of

20 kN is applied on the bar, calculate the stresses in each section

and the total elongation of the bar.

12. For a given material, Young’s modulus (E) and rigidity

modulus (G) are 120 109 N / m2 and 50 109 N / m2

respectively.

Find the bulk modulus and lateral contraction of a round bar of

36 mm diameter and 2·5 m long, when it is stretched by 2·5 mm.

13. Select a suitable diameter of a solid shaft to transmit 110 kW

power at 240 r.p.m., if the allowable stress is not to exceed

70 N / mm2 and twist not to exceed 1º in a length of 3 m.

14. Explain with the help of line sketches the working principle of 4-

stroke petrol engine.

* 15. Distinguish between diesel engine and petrol engine.

16. Desc*ribe the working of a La Mont boiler with a neat sketch.

17. Distinguish between impulse and reaction turbines.

18. (a) Write the any five applications of lubricants.

(b) Explain about collar bearing with a neat sketch.

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