(DEE 211) II/IV B.Tech. DEGREE EXAMINATION, JUNE (Examination at the end of First Semester) Electricals and Electronics. Paper I MATHEMATICS III

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1 (DEE 11) II/IV B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of First Semester) Time : Three hours Electricals and Electronics Paper I MATHEMATICS III Maximum : 75 marks Answer question No. 1 compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Define periodic function. (c) (d) (e) Write Parseval s formula. Define Fourier integral. Define Fourier cosine transform. Write formula for half range cosine series. (f) Show that = E 1.

2 (g) Show that 1/ 1/ S = E E. (h) Explain Bisection method. (i) (j) Write Gauss s Stirling s formula. Write Newton s Backward interpolation formula. (k) Define interpolation. (l) Define Numerical differentiation. (m) Write Simpson 1/3 rule. (n) Write Euler s formula. (o) Write Newton-Raphson iteration formula. UNIT I. (a) If f ( x) = cosx, expand ( x) series in the interval ( π, π ). f as a Fourier (DEE 11)

3 Find the cosine and sine series for f ( x) = x in the interval π = x π. Hence show that UNIT II 3. (a) (i) Solve the integral equation (ii) 0 ( x) λ f cosλx dx = e. Find the Fourier transform of 1 x if x < 1 f ( x) =. 0 if x > 1 Apply Gauss-Seidal iteration method to solve the equations 83x + 11y 4z = 95 3x + 8y + 9z = 71 7x + 5y + 13z = 104. UNIT III 4. (a) Estimate the values of f ( ) and ( 4) the following available data : x : f ( x) : f from 3 (DEE 11)

4 From the following table find the values of dy d y and at x =. 03. dx dx x : y : UNIT IV 1 5. (a) (i) Use trapezoidal rule to evaluate x 3 dx 0 considering five sub-intervals. dx (ii) Evaluate 1 + x 1 0 1/3 rule taking h = 1/ 4. using Simpson s Using Runge-Kutta method of order 4, find dy 1 y ( 0.) given that = 3 x + y, y( 0) = 1, dx taking h = (DEE 11)

5 (DEE 1) B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of Second Year) Electricals and Electronics Paper II NETWORK ANALYSIS I Time : Three hours Maximum : 75 marks Answer Question No.1 compulsory. Answer ONE question from each Unit. (15 1 = 15 marks) (4 15 = 60 marks) 1. (a) Define dependent sources. (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) Write expression for energy stored in Inductor. State super position theorem. State Maximum power transfer theorem. Defined KVL. Explain RMS value of a periodic wave. What is the condition resonance for a series R-L-C circuit? Define Power factor. Where do you use parallel resonance principle? Write time constant for series R-C circuit. Explain initial value in Laplace Transform. What are initial conditions? (m) What is natural response of circuit? (n) (o) Write expression Impedance (z) for a series R-L-C circuit when subjected to sinusoidal voltages. Draw power Triangle for R-L circuit. UNIT I. (a) Use super position to find i in the circuit shown below.

6 Calculate the current in 50 Ω resistor in the network shown below, using Mesh analysis. 3. (a) Use model analysis to find power dissipated in 10 Ω resistor in the circuit shown below. Find single source equivalent circuit for the following. UNIT II 4. (a) Find thevenin's equivalent circuit considering R3 as a load in the Fig. Shown below. Find the power loss in 1 Ω resistor using Norton's theorem shown below. (DEE 1)

7 5. (a) An inductive circuit takes 5 A from a 00V supply at a power factor of 0.8 lag. Calculate (i) (ii) The impedance Resistance (iii) Reactance (iv) The phase angle (v) The volt amperes (vi) Reactive power (vii) Active power. Find the average rms and from factor for the following waveform. UNIT III 6. (a) For the series circuit shown below, calculate (i) (ii) The capacitance to give resonance Voltage across Inductance and the capacitance and (iii) A factor of the circuit. For the circuit shown, find the value of Rc for when the given circuit is resonant. 3 (DEE 1)

8 7. (a) Determine v for the network such that the current in ( + j6) Impedance is zero. Find Norton's equivalent current of the circuit shown in Fig. UNIT IV 8. (a) Define initial and Final value theorems. Calculate i(t) in the circuit shown in Fig for t > 0. Assume that the switch is in closed position for long time and opened at t = (a) Explain the advantages of Laplace transform for solving differential equation. Of sinusoidal voltage v(t) = 5 sin 10 t is applied at t = 0 to the circuit shown below. Find the expression for i(t). 4 (DEE 1)

9 (DEE 13) II/IV B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of First Semester) Electricals and Electronics Paper III ELECTRONIC DEVICES Time : Three hours All questions carry equal marks. Maximum : 75 marks Answer Question No. 1 compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) How is horizontal electron beam produced in a CRT? (c) (d) (e) (f) (g) What is the forbidden energy gap and its significance in semi conductors? Define mean life time of a carrier. Define Fermi level of a semiconductor. What are the applications of Varactor Diode? What is the importance of peak inverse voltage? How does Zener diode maintain constant voltage across the load?

10 (h) (i) (j) (k) (l) State Law of j unction. Draw the input and output characteristics of CE configuration. What is Thermal runaway? How does a photo transistor differ from a BJT? Define Stability factor. (m) Draw the V-I characteristics of an UJT. (n) (o) What are the differences between SCR and Triac? How is turning off of a SCR done? UNIT I. (a) Derive the conductivity equation for an N-type and P-type semiconductors. Analyze the motion of electron in a magnetic field. 3. (a) Describe the focusing action in a CRT using electrostatic deflection. Derive the expression for electrostatic deflection sensitivity of a CRT. Define mobility. Explain how do you find mobility using Hall effect. (DEE 13)

11 UNIT II 4. (a) How does the transition capacitance vary with the depletion layer width? Explain. Explain how a Zener diode can be used as a voltage regulator. 5. (a) Explain the principle and operation of a LED and mention their advantages. Explain the operation of photo diode and state its applications. UNIT III 6. (a) Compare the CC, CB, and CE configurations of transistor. Sketch the input and output characteristics of a transistor in CB configuration and explain. 7. (a) Explain the principle and operation of a photo transistor.how it works as photo resistor. Explain the stability factor with respect to reverse saturation current. 3 (DEE 13)

12 UNIT IV 8. (a) What are the differences between depletion and enhancement type MOSFET? Explain the operation of any one. Explain the operation of UJT with the help of emitter characteristics. 9. (a) Explain the working of SCR. Draw its VI characteristics. Explain the characteristics of Diac with its operation. 4 (DEE 13)

13 (DEE 14) B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of Second Year) Electricals and Electronics Paper IV ELECTRICAL AND ELECTRONICS ENGINEERING MATERIALS Time : Three hours Maximum : 75 marks Answer question No. 1 compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) Assume any data if missing. 1. (a) Mention some applications of nano particles. (c) (d) (e) (f) (g) What is total polarization? Write about critical current density. What is zero resistivity? Write a note on fabrication of IC chip. What is average energy of a free electron? What is Josephson effect?

14 (h) Write about Magnetic moment of simple atoms. (i) (j) Explain Dielectric breakdown. Write the application of piezoelectricity. (k) Explain Wiedmann-Franz law. (l) Explain Temperature dependance of electrical resistivity in metals. (m) What are different types of superconductors? (n) What are carbon nano tubes? (o) What are copper pairs? UNIT I. (a) What are nano structured materials? Explain the synthesis and applications of nano-structured materials. (15) Explain about electrical characteristics and properties of carbon nano tubes. (15) UNIT II 3. (a) Calculate the Fermi energy of sodium at OK given the density of sodium is 970 Kg/m 3 and its atomic weight is 3. (8) Write a note on Brilliouin zones. (7) (DEE 14)

15 (c) Write about crystal growth and purification by zone refining technique. (15) UNIT III 4. (a) What are super conductors? Classify them based on magnetization behavior. (8) Explain Weiss theory and domain theory. (7) (c) Explain in detail the energy product of magnetic material. What is its importance? (8) (d) What is BCS theory and Cooper pairs? (7) UNIT IV 5. (a) What is meant by polarization? Write short notes on the different types of polarization mechanisms involved in a dielectric materials. (8) Explain crystal structure of BaTiO3. (7) (c) Discuss about Macroscopic and Microscopic electric fields. (15) 3 (DEE 14)

16 (DEE 15) II/IV B.Tech. DEGREE EXAMINATION, JUNE 010 (Examination at the end of First Semester) Electronics and Communications Paper V DIGITAL ELECTRONICS Time : Three hours Maximum : 75 marks Answer Question No.1 is Compulsory. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Convert (0ABD5)16 to decimal value. (c) (d) (e) (f) What is the difference between a latch and a flip flop? Draw the logic of a half adder and the truth table. Distinguish between s and l s compliment. Simulate EX-OR using universal gates. Define set time and hold time of a flip flop.

17 (g) (h) (i) (j) (k) (l) Write the differences between decoders and encoders. Write briefly about to tempole. Why fan out of ECL gates is higher? What are prime implicates? Define Noise margin. What are the advantages and disadvantages of k-map? (m) How does the look-ahead carry adder speed up the addition process? (n) (o) What do you mean by toggling? Define propagation delay of a flip flop. UNIT I. (a) What is a Grey code? Draw the truth table of a gray code. Convert 1001 gray code to binary. Explain the method of representing a number in s complement method. How does this differ from 1 s complement representation? Explain with an example. (DEE 15)

18 3. (a) Explain Minterms and Maxterms. Simplify the following expression and implement using any universal gate F x, y, z = xy+ xyz + xy+ xy. ( ) z UNIT II 4. (a) Explain the operation of an odd parity generator with a circuit diagram. Distinguish between multiplexer and demultiplexer. Explain the operation of a multiplexer. 5. (a) Explain the operation of error detection and correction using Hamming code. Design a full subtractor and explain its operation with the help of truth table. UNIT III 6. (a) Realize a D flip flop and a T flip flop using JK flip flops. Give their truth tables. Draw the circuit for a Mod -10 ripple counter and explain its operation with a truth table. 3 (DEE 15)

19 7. (a) Design and construct a mod 5 counter skipping 010,100 and 101 states of a binary counter using three JK flip flops. Draw the circuit diagram of a4 bit right - shift register and explain its operation. UNIT IV 8. (a) Explain the operation of a TTL NAND gate. Compare MOS and CMOS technologies. 9. (a) Which is the fastest logic family? Explain its operation. Explain sequential programmable devices. 4 (DEE 15)

20 (DEE 16) II/IV B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of First Semester) Electricals and Electronics Paper VI ELECTRO MECHANICS I Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsorily. Answer ONE question from each Unit. (1 15 = 15) (4 15 = 60) 1. (a) Explain co energy. Write an expression for energy stored in inductor. (c) Why air gap is required between rotor and stator of D.C. machine? (d) Why field core is Laminated in D.C. machines? (e) Write D.C. motor performance equation. (f) What is the purpose of commutator in a D.C. generator? (g) What is the purpose of compensating winding in a D.C. machine? (h) What is the application D.C. series motor? (i) What is the purpose starter in a D.C. motor? (j) Which winding control is used to run the motor than rated speed? (k) What is the advantage of Swin-Burne s test? (l) What is the application of amplidyne? (m) Define efficiency of D.C. generator. (n) What is the condition for maximum efficiency in D.C. machines? (o) To get more current in D.C. generators which type of winding (lap or wave) is used. UNIT I. (a) A magnetic circuit has a coil with 1000 turns. Its reluctance is expressed as 3 ( g) 10 R = MKs units, where g = air gap length in mm, between fixed and movable parts. For a coil current of amps held constant and with slow movement, calculate the change in the field energy stored, if the length of air-gap changes from cm. Calculate the mechanical force experienced by the system. Derive an expression for energy in magnetic system.

21 3. (a) A coil of an electromagnetic relay is associated with a magnetic circuit whose reluctance is given by = a + bx where a and b are positive constants decided by the details of the Magnetic circuit, in which x is the length of the air gap between fixed and movable members. If the coil is connected to an A.C. source where voltage is described by v = Vm sin wt. Find the expression for the average force on armature, with air-gap held constant at x. An electromagnetic relay with an air-gap of x cm has the current and flux-linkage +. 5 i = λ λ 0 x amps, for x < 0. 5 cm. Find the force an armature as a relationship as ( ) function of λ and x. UNIT II 4. (a) Derive an equation for EMF induced in a D.C. generator. A 4 pole wave-wound motor armature has 880 conductors and delivers 10 A. The brushed have been displaced through 3 angular degrees from the geometrical axis. Calculate (i) demagnetising amps-turns/pole (ii) cross-magneting amp-turns/pole (iii) the additional field current for neutralizing the demagnetisation of the field winding has 1100 turns/pole. 5. (a) Explain in details the process of commutation in D.C. generators. A 4-pole, D.C. shunt motor has a wave winding armature with 65 slots each containing 6 conductors. The flux per pole is 0 m Wb and the armature has a resistance of 0.15 Ω. Calculate the motor speed when the machine is operating from a 50 V supply and taking a current of 60 amp. UNIT III 6. (a) Write the applications of D.C. Motors. Two D.C. shunt generators each having an armature resistance of 0.0 Ω and a field resistance of 50 Ω operate in parallel to supply a combined load of 5000 A. Determine the common terminal voltage and the load current of each machine if the induced emfs in the two machines are 500 V and 510 V respectively. 7. (a) Explain, with neat diagram, the operation of 3 point starter. A 50 V shunt motor with armature resistance of 0.5 ohm runs at 600 rpm on full load and takes an armature current of 0 A. If the resistance of 1 ohm is placed in the armature circuit, find the speed at (i) full-load torque (ii) half full-load torque. (DEE 16)

22 UNIT IV 8. (a) Describe how you determine the efficiency of D.C. machine using Swin-Burns test. In a retardation test on a D.C. motor, with its field normally excited the speed fall from 155 to 1475 rpm in 5 seconds. With an average load of 1 kw supplied by the armature, the same speed drop occurred in 0 sec. Find out the moment of inertia of the rotating parts in kg-m. 9. (a) Explain the operation and working of an amplidyne machine as a power amplifier. A 500 V, shunt motor takes a total current of 5 A when running unloaded. The resistance of armature circuit is 0.5 ohm and the field resistance is 15 ohm. Calculate the efficiency and output when the motor is loaded and takes a current of 100 A. 3 (DEE 16)

23 (DEE 17) II/IV B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of First Semester) Electricals and Electronics Paper VII ENVIRONMENTAL STUDIES Time : Three hours Answer ALL questions. All questions carry equal marks. Maximum : 75 marks 1. Explain the following in 1 or sentences. (a) (c) (d) (e) (f) (g) Significance of environmental studies. High yielding varieties. Use of surface water. Wind energy. Estuaries. Aesthetic value of biodiversity. Global issues in environmental pollution.

24 (h) Global warming. (i) (j) Drinking water problem. Rain water harvesting. (k) Sustainable life styles. (l) Watershed management. (m) Chipko movement. (n) Environmental governance. (o) Anna Hazare. UNIT I. Explain the structure and functions of ecosystem. 3. Discuss the effect of dam on forest and tribal people. UNIT II 4. Suggest measures to control water and air pollutions in India. 5. What are the threats to biodiversity? Discuss India as a mega diversity habitat. (DEE 17)

25 UNIT III 6. Elucidate the impact of industrialisation and urbanisation an environment. 7. Describe the interaction between environment and economy. UNIT IV 8. Bring out the regulatory framework relating to environmental protection. 9. What are the major recommendations of world commission for environmental development? 3 (DEE 17)

26 (DEE 1) B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of Second Year) Electricals and Electronics Paper I MATHEMATICS IV Time : Three hours Maximum : 75 marks All questions carry equal marks. Answer Question No. 1 compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Define Analytic function. (c) (d) Define harmonic function. Write the real and imaginary parts of sinz. State Cauchej s integral theorem. (e) Determine the poles of f ( z) cotz =. (f) Define isolated singularity of f ( z). (g) Define a simple pole.

27 (h) State Taylor s series for f ( z). (i) (j) (k) (l) State Residue theorem. Define Residue. Define regular singular point of a differential equation. Write Bessel s equation. (m) Write the value of P 0 ( x). (n) Write Rodrigue s formula of Bessel s function. (o) Write the orthogonality property of Legendre polynomials. UNIT I. (a) State and prove sufficient conditions for f ( z) to be analytic. Show that the function at the origin, although satisfied at the point. 1 xy is not regular C R equations are 3. (a) Find the analytic function whose imaginary x v = e xsin y+ ycosy. part is ( ) 1 Show that the function u log( x + y ) = is harmonic and determine its conjugate. (DEE 1)

28 UNIT II 4. (a) Find the first three terms of the Taylor series 1 expansion of f ( z) = about z = i. z + 4 Evaluate circle c z = z. e z ( z 1) ( z ) dz, where C is the 5. (a) Find the Laurent s expansion of 7z f ( z) = in the region <z +1 < 3. z + 1 zz ( ) ( ) Use Cauchy s integral formula to evaluate z +, where C is c ( z 3z ) dz UNIT III 1 z =. 6. (a) Determine the poles of the function z f ( z) = and the residue at each z 1 z + ( ) ( ) c pole, Hence evaluate f ( z) Circle z =. 5. dz, where C is the 3 (DEE 1)

29 Evaluate C circle z =. z z 1 ( z + 1)( z 3) dz, where C is the coswx 7. (a) Evaluate dx, w 0. x d y Solve in series the equation + x y = 0. dx UNIT IV 8. (a) Prove that J n ( x) = cos( nθ xsinθ ) dθ being an integer. 1 π n Show that P ( x) = ( ) P ( x) n 1 π. 9. (a) Prove that P ( x) P ( x) n n n dx = 0, if m n., n Prove that d dx ( xj J ) x( J J ) n n+ 1 = n n (DEE 1)

30 (DEE ) B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of Second Year) Electricals and Electronics Paper II ELECTRONIC CIRCUITS I Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Define early effect. (c) (d) (e) Define stability factor. What do you mean by rectification? Draw the diode clamping circuit. Draw hybrid parameter model of transistor. (f) Define α. (g) Explain the functions of rectifier. (h) Give the relationship between α and β. (i) Draw the hybrid π model of a transistor.

31 (j) (k) (l) Define transconductance in a FET. Give the relation between transconductance and amplification factor in a FET. Draw circuit diagram of Darlington pair. (m) What is the significance of by pass capacitor in amplifiers? (n) (o) Draw the equivalent circuit of FET in small signal model. What is cascade amplifier? UNIT I. (a) Derive expressions of DC or average value of voltage and RMS value of voltage of a fullwave rectifier with resistive load. Compare halfwave and fullwave rectifiers. 3. (a) Draw and explain the RC high pass filter with step and pulse input are give to that circuits. Explain about double clipping. (DEE )

32 UNIT II 4. (a) Obtain the following using h-parameter model for CE transistor amplifier. (i) AI (ii) Zi (iii) AV (iv) Z0. Explain Millers theorem. 5. (a) Explain about cascade transistor configuration. Analyse the two stage transistor amplifier at low frequencies. UNIT III 6. (a) How high frequency low frequency is effected with cascaded amplifiers, and also draw the frequency response of cascade amplifiers? Derive the hybrid π parameters. 7. (a) Derive the expression for the CE short circuit current gain ( A I ) as a function of frequency. Draw the CE Amplifier response curve for both resistive and inductive loads and obtain an expression for gain band width product. 3 (DEE )

33 UNIT IV 8. (a) Explain CE CE cascade Amplifier, and draw its frequency response. Explain FET Act as a VDR. 9. (a) For p-channel JFET if I DSS = 4 ma and V P = 4 V, calculate Quiescent values of I D, V GS, V DS Compare BJT and JFET. 4 (DEE )

34 (DEE 3) B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of Second Year) Electricals and Electronics Paper III ELECTROMAGNETIC FIELD THEORY Time : Three hours Maximum : 75 marks Answer question No. 1 compulsorily. Answer ONE question from each Unit. 1. (a) List the different charge distribution. (c) (d) (e) (f) (g) Express the Gauss in differential form. What is meant by equipotential surface? Give the expression of potential gradient. What is the conduction current? What is the significance of divergence? Define emperis circuital law? (h) What is magnetic dipole? (i) (j) Differentiate solenoid and toroid? Express the Faraday's law in integral form.

35 (k) Write the Lorenz force equation. (l) State Poynting theorem. (m) Write the expression for wave equation for time varying field. (n) What is lossy dielectrics? (o) State Poisson s equation. UNIT I. (a) State and prove Gauss's law and determine the field due to an infinite line change using this. A circular disc of 0 cm radius in charged uniformly with a total charge of 40 nc. What is the field intensity at a point on its axis, 10 cm away? 3. (a) Derive the boundary conditions for perfect dielectric materials. Given D = 10 sinθ r + cos θ θ in spherical coordinates, find the charge density. UNIT II 4. (a) Derive the expression for magnetic field intensity at a point due to an infinite length of current conductor. (DEE 3)

36 A current carrying wire is bent in to the shape of a regular polygon of N sides that can be inscribed in a circle of radius R. Assuming that the current in the wire in I, find the magnetic flux density B at the center of the circle in terms of N, R and I. µ J 5. (a) Show that A = dv, where A is the 4π r vector magnetic potential and J is the current density. The field Intensity at a radius of 0.5 m from a long straight conductor is A/m. Find the current carried by the conductor. UNIT III 6. (a) Derive the wave equation from Maxwell's equations for free space and charge free region. Given a non magnetic material having E =.5 and σ =10 4 mho/m. Find r numerical values at.5 MHz for (i) (ii) the loss tangent the attenuation constant (iii) the intrinsic impedance. 3 (DEE 3)

37 7. (a) Write Maxwell's equation in point form and in integral form. Derive continuity equation from Maxwell's equations. UNIT IV 8. (a) Shows that the Poynting Vector P = E H. Find α, β and the decibels per meter attenuation in a lossy dielectric E r = 4, σ = 0.1S / m, µ = µ at a frequency ( ) of.45 GHz. 9. Write short notes on the following : (a) (c) Uniform plane wave. Power density in an electro magnetic field Skin effect. 0 4 (DEE 3)

38 (DEE 4) Time : Three hours B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of Second Year) ELECTRICALS AND ELECTRONICS Paper IV NETWORK ANALYSIS II Answer Question No. 1 compulsorily. Answer ONE question from each Unit. 1. (a) State reciprocity theorem in terms of Z-parameters. Define voltage transfer function. (c) What are the properties of complete incidence matrix? (d) What is a planar graph? (e) What are necessary conditions for a transfer function? (f) What is scaling factor? (g) What are inverse transmission on parameters? (h) What is a co-tree? (i) What is self inductance? (j) What is the total power in a 3 φ circuit? (k) What is a balanced circuit? (l) What is dot convention? (m) What are dual networks? (n) What are M-filters? (o) What is the relationship between V ph and V L in a star connected network? UNIT I. (a) For the network shown find f-cut set matrix and a directed graph. Maximum : 75 marks (1 15 = 15) (4 15 = 60) Obtain the z-parameters of the circuit.

39 3. (a) Obtain z-parameters of the circuit shown in Fig. Obtain y-parameters of the circuit. UNIT II 4. (a) Find out the step response of the circuit. Determine the impulse response of H t t 5. (a) The impulse response of a network is given as ( e e ) find the transfer function. Plot the pole zero plot of the following function in S-plane. S + 4S + 3 F ( S) =. S + 6S + 8 (DEE 4)

40 UNIT III 6. (a) Obtain the Laplace equivalent of the transformer shown. Design a second order Butterworth LPF with cut off frequency KHz. 7. (a) Show that the transfer function of first order HPF is of the form AV ( S) 1 = AV w0 S 0 + Show that the transfer function of a second order HPF is given by A V ( S) 1 =. AV0 ~ w0 ( w0 / S) + K + 1 S UNIT IV 8. (a) What are the advantages of 3 φ systems? Explain how a star connected network can be transformed to its equivalent delta connected network. 9. (a) A 3 wire 400 V ABC system supplies a delta connected load Z = 0 30Ω, Z = 15 0Ω and Z = 5 30Ω. Find the currents and total power. BC CA Explain how total power in a 3 φ circuit can be measured using two wattmeters with the help of phasor diagram. AB. 1 3 (DEE 4)

41 (DEE 5) B.Tech. DEGREE EXAMINATION, JUNE 010. (Examination at the end of Second Year) Electricals and Electronics Paper V PRIME MOVERS AND PUMPS Time : Three hours Maximum : 75 marks Answer Question No. 1 compulsorily. (1 15 = 15) Answer ONE question from each Unit. (4 15 = 60) 1. (a) Define specific weight. (c) (d) (e) (f) (g) (h) What are the different types of pumps? Name them. What are the different types of turbines? Name them. What is cavitation? What is relative density? What is the force of jet impinging normally on a fixed plate? What in the efficiency of centrifugal pump? What is the specific speed?

42 (i) (j) (k) (l) What is draft tube? Define thermodynamic system. What is enthalpy? What is the relation between CV and CP? (m) Give two differences between SI and CI engines. (n) (o) What is regeneration? What is stage efficiency? UNIT I. (a) Derive the equation for force exerted by a jet on fixed curved Vane at the centre. A tank 0 m deep and 70 m circle is layered with 8 m of oil, 6 m of water and 4 m of mercury. Determine the total hydraulic force and resultant centre of pressure on the side. Specific gravity of oil is and that of Hg (Mercury) in (a) Derive an expression for efficiency of centrifugal pump. Explain with neat sketch, the working of a single stage centrifugal pump. (DEE 5)

43 UNIT II 4. (a) What do you understand by performance characteristic curves in reaction turbines? Explain. What are the differences between Impulse and reaction turbines? 5. (a) What are elements considered while designing a Pelton wheel? Explain. What are the different types of impulse turbines? Explain any one with neat diagram. UNIT III 6. (a) Explain the differences between Otto cycle and diesel cycle. In an air standard Otto cycle, the compression ratio in 8, and at the begining of isentropic compression the temperature is 15 C and the pressure is 0.1 MPa. Heat in added until the temperature at the end of the constant volume process is 100 C. Calculate (i) (ii) The heat supplied/kg of air The cycle efficiency (iii) The M.E.P. 3 (DEE 5)

44 7. (a) Derive an expression relationship between CP, CV and r. Derive an expression for efficiency of Brayton cycle. UNIT IV 8. (a) Explain the differences between two stroke and four stroke engines. Explain the performance of IC engines. 9. (a) Explain with line diagram of closed cycle gas turbine. Explain the effect of inter cool on the efficiency gas turbine. 4 (DEE 5)

45 (DEE 6) B.Tech DEGREE EXAMINATION, JUNE 010. (Examination at the end of Second Year) Electricals and Electronics Paper VI ELECTRO MECHANICS II Time : Three hours Maximum : 75 marks Answer question No. 1 compulsorily. Answer ONE question from each Unit. 1. (a) What is a step down transformer? (c) What is the function of core in a transformer? What is a shell type transformer? (d) If V1 = 100 V ; the transformation ratio is ; what is the value of V. (e) (f) (g) Mention the factors on which eddy unit loss depends. Did core losses are dependent as power factor. Draw the load Vo efficiency characteristic of a transformer. (h) What is the purpose of short circuit test as transformer?

46 (i) What is the advantage of Y Y connected transformer? (j) What is the stationary element in an Induction motor? (k) What is the slip ring Induction motor? (l) The given Induction motor is supplied at 50 C/s frequency and it has 6 poles, what is the value of synchronous speed. (m) What is the application of shaded pole motor? (n) What is the slip when speed of the Induction motor is Ns? (o) Explain the advantages of sumpner s Test. UNIT I. (a) Derive the e.m.f. equation of a single phase transformer. A 5 KVA, single phase transformer has 50 turns on the primary and 40 turns on the secondary. The primary is connected to 1500 V, 50 Hz supply. Calculate : (i) (ii) Primary and secondary currents on full load Secondary emf. (DEE 6)

47 3. Explain OC and S.C tests on a single phase transformer in detail. UNIT II 4. (a) Draw the configurations of, Y, Y, Y Y connected 3-φ transformers. An auto transformer supplies a load of 3 KW at 115 V at unity power factor. If the applied primary voltage is 30 V. Calculate the power transferred to the load (i) inductively and (ii) conductively. 5. (a) What are the conditions to be satisfied for parallel operation of two single phase transformers? Explain Tap charging of transformers and what is its use. UNIT III 6. (a) Explain the constructional details of a 3-φ Induction Motor. A 3-φ Induction motor is word for 4 poles and is supplied from 50 C/s system. Calculate : (i) synchronous speed (ii) motor speed when slip is 4% (iii) motor frequency when the rotor runs at 600 rpm. 3 (DEE 6)

48 7. (a) Give the procedural steps to draw circle diagram of a 3-φ Induction motor. A 3-phase, 400/00 V, Y-Y connected wound rotor Induction motor has 0.06 Ω rotor resistance and 0.3 Ω stand still reactance per phase. Find the additional resistance required in the rotor circuit to make the starting torque equal to maximum torque. UNIT IV 8. (a) Explain star/delta starter with the help of a neat sketch. What is a Double Cage Induction Motor and draw its equivalent circuit? 9. (a) Explain the operation of a capacitor start and run single phase Induction motor and what are its applications. Explain the required of starting winding in a single phase induction motor. 4 (DEE 6)