UNIT 2

UNIT 1BEE SET-1 PART A 1. What are the differences between dependent and independent sources. 2. Write the volt-ampere relations of R, L, C parameters. 3. Define the average and root mean square value of an alternating quantity. PART B

.The resistance of a light dependent resistor: (a) falls with increasing light level (b) increases with increasing light level (c) remains constant irrespective of light level Ans: a2. If the resistance of a material falls with increasing temperature it is said to have: (a) negative temperature coefficient (b) positive temperature coefficient (c) zero temperature coefficient Ans: a3. The circuit symbol shown is a: (a) fixed resistor (b) preset resistor (c) variable resistor Ans: c4. Two capacitors, each of 15 F, are connected in series. The capacitance of the combination will be: (a) 7.5F (b) 15F (c) 30F Ans:a5. The charge, Q, present in a capacitor is given by the relationship: (a) Q = C / V (b) Q = C V (c) Q = C V2 Ans:b6. Whenever current is supplied by a source its terminal voltage(a) increases(b)decreases (c)remains constant Ans:b7. Which of the following can not be connected in series unless they are identical?(a) voltage source(b) current source(c)both of the above(d) resistance Ans: b8. Kirchhoffs second law is based on law of conservation of(a)charge (b) energy(c) momentum(d)mass Ans:b9. A terminal where more than two branches met is called: (a) Node(b) Terminus(c) Loop(d) None of the above Ans:a10. If there are 'b' branches and 'n' nodes the number of equations will be:(a) n-1(b) b(c) b-n-1(d) b-n+1 Ans:d11. Kirchhoff's laws are applicable to circuits with:(a) Distributed parameters(b) Lumped parameters(c) Passive elements(d) Non-linear resistances Ans:a12. An ideal current source has:(a) Zero internal conductance(b) Zero internal resistance(c) Zero voltage on no load(d) Zero ripple Ans

29. Mesh analysis is based on .(a)KVL (b)KCL(c)Ohms law(d)Amperes law Ans:a

30. The nodal method of circuit analysis is based on (a)KVL (b)KCL(c)Ohms law(d)Amperes law Ans:b

31. The network has 10 nodes and 17 branches. The number of different node pair voltage would be(a)25(b)45(c)47(d)55 Ans:b

34. The total power in a series circuit is 10W. There are five equal valve resistors in the circuit. How much power does each resistor dissipates(a)1 W(b)2 W(c)3 W (d)4 W Ans:b

35. Six light bulbs are connected in parallel across 110V. Each bulb is related at 75 W. How much current flows through each bulb.

(a)5 A(b)0.682 A(c)3.5A (d)0.59A Ans:b

36. If R1 and R2 are connected in series to the voltage of V volts, then drop across R2 is(a) R2 = V . R2/(R1+R2)(b) R2 = V . R2/(R1-R2) (c) R2 = V . R1/(R1+R2) (d) R2 = V . R1/(R1-R2) Ans:a 37. If R1 and R2 are connected in paralell to the voltage of V volts, then current through R2 is(a) I2 = I . R1/(R1+R2) (b) I2 = I . R1/(R1-R2) (c) I2 = I . R2/(R1+R2) (d) I2 = I . R2/(R1-R2) Ans:a

38. Determine the current if a 10 coulomb charge passes a point in 0.5 sec(a) 20A (b) 22A(c) 10A (d) 14A Ans:a

BEE SET-2 PART A

1. Draw the impedance triangle of series R-L and R-C circuits.2. Define the quality factor. What is its significance?3. Define reluctance and magnetic flux.

PART B

40. Determine the total inductance of a parallel combination of 100 mH, 50mH and 10mH..(a) 7.69mH(b) 6.69mH (c) 0.69mH (d) 9.69mH Ans:a

41. Determine the charge when C = 0.001 F and v = 1 kV(a) 1c (b) 0.11c(c) 1.2c(d) 0.001c Ans:a

42. If the voltage across a given capacitor is increased, does the amount of stored energy(a) increases(b) decreases(c) remains constant(d) either increases or decreases Ans:a

43. How much energy is stored by a 0.05F capacitor with a voltage of 100V.(a) 0.025J(b) 0.125J (c) 1.25J (d) 0.5J Ans:a

44. Which of the following is an ideal voltage source(a) voltage dependent of current.(b) voltage Independent of current.(c) current dependent of voltage(d) current independent of voltage Ans:b

45. How much energy is stored by a 100mH inductance with a current of 1A?(a) 0.005J(b) 0.56J (c) 1.625J (d) 0.05J Ans:d

46. If a resistor has 5.5 V across it and 3mA flowing through it, what is the power(a) 12.5mWs (b) 10.9mWs(c) 16.5mWs (d) 17.5mWs Ans:c

47. In series as well as parallel resonant circuit, increase in resistance would caus(a)decrease band width of both the circuits. (b)increase bandwidth of both the circuits. (c)decrease in bandwidth in series circuits & increase in bandwidth in parallel circuits. (d)increase in bandwidth in parallel circuits & decrease in bandwidth in series circuits. Ans:b

48. A certain AC circuit has resistance of 10 and impedance of 20 . The phase angle of voltage and current of the circuit is(a) 50(b) 30(c) 60 (d) 90 Ans:c49. The time constant of an RL circuit is 1 second and its inductor is 8 H, the resistance of the coil is(a) 8 (b) 1/8(c) 1/2(d) 3/4 Ans:b50. To a highly inductive circuit, a small capacitance is added in series. The angle between voltage and current will(a) increases(b) decreases(c) remains constant(d) either increases or decreases Ans:b51. In what connection we get neutral?(a)Star. (b)Delta. (c)Mesh. (d)Both A and B. Ans:a52. What is the relation between line voltage and phase voltage in case of delta connection?(a)VL = VP. (b)VL = 1/ 3 VP. (c)VL = 3 VP. (d)None of these Ans:a53. The value of supply voltage for 400 W, 4 load is(a) 40V(b) 400V(c) 20V (d) 200V Ans:a4. Kirchhoffs laws are valid for(a)linear circuit only. (b)passive time invariant circuits. (c)non-linear circuits only. (d)both linear and non-linear circuits. Ans:a

55. An electrical circuit with 10 branches and 7 nodes will have(a)10 loop equations. (b)7 loop equations. (c)3 loop equations. (d)4 loop equations. Ans:d

59.Resistance is expressed in terms of(a)ohms(b)mhos(c)ohm/m(d)mho/m Ans:a

60.Inductance is expressed in terms of(a)ohms(b)mhos(c)henry (d)farad Ans:c1. If E1 = Asint and E2 = Asin(t ), then (a)E1 lags E2 by 2. (b)E1 leads E2 by . (c)E2 leads E1 by . (d)E2 leads E1 by . Ans:b

2. Two sinusoidal quantities are said to be phase quadrature, when their phase difference is(a)0. (b)30. (c)45. (d)90. Ans:d

BEE SET-3PART A 1. List the properties of incidence matrix. 2. State the maximum power transfer theorem. 3.Obtain the expressions for star-delta and delta-star equivalence of resistive network.

PART B

3. The equation for 25 cycles current sine wave having rms value of 30 amps, will be(a)42.4sin50t. (b)30sin50t. (c)30sin25t. (d)42.4sin25t. Ans:a

4. What will be the rms value of rectangular wave with amplitude 10 V?(a)52 V. (b)10 V. (c)11.2 V. (d)7.7 V. Ans:b

5. The rms value of sinusoidal voltage wave V = 200sint, is(a)1002 V. (b)200 V. (c)100 V. (d)2002 V. Ans:a

6. If one cycle of AC waveform occurs every millisecond, the frequency will be(a)100 Hz. (b)1000 Hz. (c)50 Hz. (d)10 kHz. Ans:b

7. The rms value of the voltage U(t)= 3 + 4cos(3t) (a)5 V. (b)4.123 V. (c)7 V. (d){3 + 2(1.141)} V. Ans:b

11. The power factor of ac circuit lies betweena) 0 and 1b) -1 and 1c) 0 and -1d) None of the above Ans:a

12. A Circuit of zero lagging power factor behaves as:a) An inductive circuitb) A capacitive circuitc) R-L circuitd) R-C circuit Ans:a

13. In order to improve the power factor which device should be connected to the power system:a) Series capacitorb) Shunt capacitorc) Series inductord) Shunt inductor Ans:b

4. The power factor of an ac circuit is equal to:a) Cosine of the phase angleb) Sine of the phase anglec) Tangent of the phase angled) Cotangent of the phase angle Ans:a

15. In an ac circuit i x sin (Phi) is called the __ component of the current:a) Watlessb) Reactivec) Quadratured) All the above Ans:d

16. The heat developed in an electric iron is attributed to __ powera) Apparentb) Reactivec) Trued) True and reactive Ans:c

17. When the power factor in the transmission line is leading, which device is employed at substation to reduce the power factor: a) CVTb) Reactorc) Synchronous condenserd) None of the above Ans:b

18. In a circuit low reactive power compared to true power indicates:a) Low power factorb) High power factorc) Low efficiencyd) High efficiency Ans:b

19. The rating of given on the name plate of a transformer indicates the: a) True power which it can supplyb) Apparent power which it can supplyc) Apparent power which it draws from the supply mainsd) True power which it draws from the supply mains Ans:b

20. An a.c. current given by i = 14.14 sin (t + /6) has an r.m.s value of amperes.(a) 10(b) 14.14(c) 1.96(d) 7.07 Ans:a

2. If e1 = A sin t and e2 = B sin (t ), then(a) e1 lags e2 by (b) e2 lags e1 by (c) e2 leads e1 by (d) e1 is in phase with e2 Ans:b

23. The r.m.s. value of a half-wave rectified current is 10A, its value for full-wave rectification would be amperes.(a) 20(b) 14.14(c) 20/(d) 40/ Ans:b

24. The r.m.s. value of sinusoidal a.c. current is equal to its value at an angle of degree(a) 60 (b) 45 (c) 30 (d) 90 Ans:b

25. wo sinusoidal currents are given by the equations : i1 = 10 sin (t + /3) and i2 = 15sin (t /4). The phase difference between them is degrees.(a) 105(b) 75(c) 15(d) 60 Ans:a

26. As sine wave has a frequency of 50 Hz. Its angular frequency is radian/second.(a) 50/(b) 50/2 (c) 50 (d) 100 Ans:d

BEE SET-4PART A

1. Explain the procedure to draw the locus diagram of R-L series circuit when L is varying? 2. A coil of inductance 0.0805 H takes a current of 5 A when connected in series with a 50 f loss-free capacitor across a 240 V, 50 Hz supply. Calculate (i) resistance of the coil (ii)power factor of the coil (iii) the overall power factor. Sketch the phasor diagram.3. Show that average power consumed by a pure inductor and a pure capacitor is zero.

PART B27. An a.c. current is given by i = 100 sin 100. It will achieve a value of 50 A after second.(a) 1/600(b) 1/300(c) 1/1800(d) 1/900 Ans:a

9. The current through a resistor has a waveform as shown in Fig. 11.67. The reading shown by a moving coil ammeter will be ampere.(a) 5/ 2 (b) 2.5/ 2(c) 5/ (d) 5 Ans:c

30. How many cycles does a sine wave go through in 10 sec when its frequency is 60 Hz.

(a)600cycles(b) 400cycles(c) 500cycles(d) 650cycles Ans:a

31. If the peak value of a certain sine wave voltage is 10 V, What is the peak to peak value.

(a)20V(b)30V(c)25V(d)35V Ans:a

32. If the peak value of a certain sine wave voltage is 5 V, What is the RMS value

(a)1.2V(b)2.5V(c)3.535V(d)3.9V Ans:c

33. What is the average value of a sine wave over a full cycle?

(a)zero (b)one(c)two(d)four Ans:a

34. A sinusoidal current has peak value of 12A. what is its average value

(a)6.4A(b)7.64A(c)9.9A(d)7A Ans:b

35. In a pure resistor, the voltage and current are

(a)out of phase(b)in phase(c)both a and b(d)none of the above Ans:b

36. The rms current through a 10 k resistor is 5mA. What is the rms voltage drop across the Resistor

(a)10V(b)30V(c)50V(d)40V Ans:c

37. When the frequency of applied voltage in a series RL circuit is increased, what happens to the Inductive reactance?

(a)increases(b)decreases(c)remains constant(d)first increases then decreases Ans:a

38. What is the phase angle between the inductor current and the applied voltage in a parallel RL circuit?

(a) 60degrees(b) 90degrees(c) 45degrees(d) 30degrees Ans:b

39. The phasor combination of resistive power and reactive power is called

(a)real power (b)reactive power(c)apparent power(d)none of the above Ans:c

40. Apparent power expressed in

(a) volt-amperes(b)newton-meter(c)KW(d)KVAR Ans:a

41. A power factor of 0 indicates

(a) purely resistive element(b) purely inductive element(c) purely capacitive element(d) none of the above Ans:a

42. Form factor is defined as ratio of

(a) average value to rms value.(b) rms value to average value.(c) maximum value to rms value.(d) rms value to maximum value. Ans:b

43. Peak factor is defined as ratio of(a) average value to rms value.(b) rms value to average value.(c) maximum value to rms value.(d) rms value to maximum value. Ans:c

44. In what connection we get neutral?

(a)star(b)delta(c)mesh(d)both a & b Ans:a

45. What is the relation between line voltage and phase voltage in case of delta connection?

(a) VL = VP(b) VL = 1/ 3 VP.(c) VL = 3 VP(d) None of these. Ans:a

8. A reactance having an inductor of 0.15 H is connected in series with 10 resistance What will be the inductive reactance? (a)48.15 . (b)47.1 . (c)1.5 . (d)None of these. Ans:b

49. A series circuit consists of R = 20 , L = 20 mH, and AC supply 60 V with f = 100 Hz. The voltage drop across R is

(a)30.6 V. (b)50.8 V. (c)40.8 V. (d)24.4 V . Ans:b