# Electrical Engineering Mastery Test 2 | REE Pre-Board Exam

(Last Updated On: October 16, 2020) This is the Pre-board Exams in Electrical Engineering 2 composed of previous REE Board Exams Questions and cautiously selected questions from various topics in Communications that could possibly be given in the board. Choose, familiarize, and test yourself so that you will know the taste of the Board Exam Questions. Read each questions and choices carefully! Choose the best answer.

#### Start Pre-board in Electrical Engineering Mastery Test 2

Choose the letter of the best answer in each questions.

1. A 125 KVA distribution transformer with 4% impedance is connected in parallel with another transformer rated 75 KVA and with 3% impedance. Both have same voltage ratio. (Neglect resistance of each transformer). The total toad is 140 KVA at 85% power factor. How much load does each carry?

A. 80.5 KVA/59.5 KVA

B. 77.78 KVA/62.22 KVA

C. 80 KVA/60 KVA

D. 87.5 KVA/52.S KVA

Solution:

2. A 5 MVA, 13.8 KV/480 V, 5% impedance transformer is tapped at 13.8 kV line where the Thevenin’s equivalent impedance is 1/2 ohm. Determine the fault current at the primary for a three-phase fault at the secondary.

A. 10,500 amperes

B. 3300 amperes

C. 4200 amperes

D. 6050 amperes

Solution:

3. Three resistors of 10-, !5-, and 20-ohm each are connected parallel. What is the equivalent resistance?

A. 45 ohms

B. 17.2 ohms

C. 0.22 ohm

D. 4.62 ohms

Solution:

4. Two alternators are driven by shunt motors. The shunt motors have speed-load drop characteristics of 3% and 4% respectively. The alternators are in parallel and each carrying 50 kw. There is no automatic speed-load control. An additional 50 kw is switched on. What are the resulting loads of the alternators assuming that the speed-load control of each is not adjusted?

A. 78.57 kW/71.43 kW

B. 82.51 kW/67.49 kW

C. 75 kW/75 kW

D. 80.31 kw/69.69 kW

Solution:

5. A 25 ohm resistor connected in series with a coil of 50 ohm resistance and 150 mH inductance. What is the power factor of the circuit?

A. 85%

B. 80%

C. 90%

D. 75%

Solution:

6. The current loads of four circuits are as follows:

Circuit no. 1 — 25 amperes

Circuit no. 2 — 38 amperes

Circuit no. 3 — 18 amperes

Circuit no. 4 — 45 amperes

If the diversity factor is 1 what is the minimum ampacity of the feeder conductor?

A. 126 amperes

B. 189 amperes

C. 84 amperes

D. 152 amperes

Solution:

7. A generator supplies three phase power to balance load. The voltage is 230 volts, the current is 1 8 amperes and the power factor is 85%. What is the power?

A. 3.6 kW

B. 1.6 kW

C. 6.1 kW

D. 1.4 kW

Solution:

8. A power plant gets water from a dam from a height of 122.45 meters at the rate of 1000 cubic meters per minute. If the output of the plant is 15,000 kW, what is the plant efficiency?

A. 80%

B. 70%

C. 75%

D. 65%

Solution:

9. In fission, energy is produced when,

A. chemical compound splits into its constituents

B. nuclear particles combine

C. nuclear particles split

D. molecules combine

Solution:

10. A magnetic circuit consists of silicon steel of 3000 permeability and an air gap. The length of the steel core is 10 cm. and the air gap is 2 cm. Both have same cross section of 1.5 sq. cm. A current of 1/2 ampere flows through the windings to produce 2351 maxwells flux. How many turns are there in the coil?

A. 4120 turns

B. 5000 turns

C. 2500 turns

D. 1250 turns

Solution:

11. The three phase unbalanced currents are:

Ia = 10 cis (-30°)

Ib = 0

Ic = 10 cis 150°

Find the negative sequence current of phase a.s

A. 8.66 cis 30°

B. 5.77 cis (-60°)

c. -5.77

D. 5.77

Solution:

12. A 230 kV transmission line has an impedance of 50 cis 78° ohms and a capacitive reactance of 1200 ohms, It transmits the power of a base load plant. On a certain dry season the sending end power is 100 MW at 235 kV and 95% power factor continuously for a period of one month. If cost of generation is Php 1.30 pesos per kWhr, what is the cost of the line losses for the one month period?

A, Php 565,000

B. Php 12.2 million

C. Php 5.6 million

D. Php 2.2 milion

Solution:

13. What arrester nominal rating shall be used in a 34.5 kV ungrounded system?

A. 27 kV

B. 42  kV

C. 22 kV

D. 35 kV

Solution:

14. A power customer draws power at 220 volts from a transformers on a pole, Current transformer with ratio of 200/5 are used to meter the electrical usage. What is the multiplier of the kWhr and demand meters?

A. 40

B. 200

c. 100

D. 80

Solution:

15. A single phase induction motor is rated 5 HP, 75% power factor and 220 volts. What approximate size of capacitor is necessary to raise the power factor to about 95%?

A. 3 KVAR

B. 2 KVAR

C. 2.5 KVAR

D. 3.5 KVAR

Solution:

16. It is a very powerful small component of a computer. Which one?

A. diode

B. triode

C. chip

D internet

Solution:

17. A DC ammeter has an internal resistance of 0.1 ohm. A shunt of 1.010 x 10-3 ohm is connected to the ammeter. What is the multiplier of the set up?

A, 80

B. 100

c. 50

D. 10

Solution:

18. Three impedance, -j10, j10 and 10 ohms are wye connected. Determine the impedance of an equivalent delta.

A. 12.5, j12.5, -12.5 ohms

B. 10, j10, -j10 ohms

C. j8.5, -j12.5, 8 ohms

D. 5, j5, -j5 ohms

Solution:

19. TV signal is transmitted to the air thru ______.

A. electron transmitter

B. cyclon

C. antenna

D. sender

Solution:

20. Which one of the following is not one of the classes of surge arresters?

A. Transmission class

B. Distribution class

C. Station class

D. Intermediate class

Solution:

21. A 50 and 100 microfarad capacitors are connected in series and across a 100 sin (ωt + 30) voltage. Write the equation of the current.

A. 1.26 sin (ωt + 120°)

B. 1.26 sin (ωt + 90°)

C. 5.65 sin (ωt + 120°)

D. 5.65 sin (ωt + 90°)

Solution:

22. Two resistances of 10 and 15 ohms, each respectively are connected in parallel. The two are then connected in series with a 5-ohm resistance. If then connected across a 12 volt battery, what are the current and power?

A. 1.2 A, 17.28 watts

B. 0.96 A, 11.52 watts

C. 1.09 A, 13.1 watts

D. 1 .5 A, 20.25 watts

Solution:

23. At a certain location in an electric system, the available fault MVA is 400 MVA. A 15 M VA, 34.5 kV/6.24 kV, 2.5% impedance, wye-wye grounded transformer is installed at that location. Determine the short circuit MVA at the secondary side of the transformer.

A. 195 MVA

B. 150 MVA

C. 90 MVA

D. 240 MVA

Solution:

24. Two resistances of 10 and 15 ohms each, respectively are connected in parallel. The two are then connected in series with a 5 ohm resistance. What is the equivalent resistance?

A. 11 ohms

B. 12 ohms

C. 10 ohms

D. 9 ohms

Solution:

25. The phase b line voitage and the phase a line current of a balanced three phase system are V = 220 sin (ωt + 210°) and I = 10 sin (ωt – 30°) respectively. What is the power of the system?

A. 1,905 watts

B. 3,300 watts

C. 5,716 watts

D. 3,810 watts

Solution:

26. The resistance of a wire is 126.48 ohms at 100°C and 100 ohms at 30°C. Determine the temperature coefficient of copper at 0°C.

A. 0.00427

B. 0.00615

C. 0.0256

D. 0.0356

Solution:

27. A certain shunt motor has an armature resistance of 0.05 ohms. It draws 50 amperes at terminal voltage of 120. Assume other miscellaneous losses at 1%. Determine the output horsepower of the motor.

A. 8.5 HP

B. 7.1 HP

C. 6.8 HP

D. 7.8 HP

Solution:

28. A coil of a 50-ohm resistance and of 150-mh inductance is connected in parallel with a 50 capacitor. What is the power factor of the circuit?

A. 80%

B. 50%

C. 70%

D. 60%

Solution:

29. A 230 kV transmission line is 100 miles long. The conductors are ACSR of 1,113,000 CM. The conductors are horizontally arranged with 20-ft spacing. The resistance per mile is 0.0969 ohm and its gmr is 0.0435 ft. What is the impedance of the line?

A. 9.69 + j95.25 0hms

B. 3.23 + j95.25 ohms

C 9.69 + j77.19 ohms

D. 3.23 + j25.93 ohms

Solution:

30. A coil of 50-ohm resistance and of 150-mH inductance is connected in parallel with a 50 μF capacitor. The source voltage is 100 sin (ωt + 30°). What is the equation of the line current?

A. 1.91 sin (ωt + 52.5°)

B. 1.25 sin (ωt + 75.5°)

C. 1.82 sin (ωt – 52.5°)

D. 1.32 sin (ωt – 75.5°)

Solution:

31. A deep well pumps water into an open reservoirs at the rate of 100 gpm. The water table is 200 ft. below the output pipe. The whole system has an overall efficiency of 70%. What shall bc the ruinimum hp of the punip?

A. 5.3 HP

B. 8.7 HP

C. 12.4 HP

D. 7.2 HP

Solution:

32. Three equal positive charges of 10 statcoulomb each are located at the vertices of an equilateral triangle of 2 cm leg. What is the magnitude of the force acting on each charge?

A. 12.5 dynes

B, 25 dynes

C. 43.3 dynes

D. 50 dynes

Solution:

33. Piezo electricity principle is applied in one of the following:

A. Ultrasonic quipment

B. Thermometer

C. Microphones

D. TV sets

Solution:

34. A load of 20 + j35 ohms is connected across a 220 volts source. Determine the power factor and the vars.

A. 49.6%, 1,042 vars

B, 85.3%, 975 vars

C. 52.2%, 1.023 vars

D. 42.3%, 1.087 vars

Solution:

35. A certain laminated steel core has a permeability of 3000. The length is 5 cm and the cross section is 2 sq. cm. What is its reluctance?

A. 7,500

B. 8.33 x 10-4

c. 1,200

D. 2.5

Solution:

36. The substation bus bar is made up of 2 inches round copper bars 20 ft. long. What is the resistance of each bar if resistivity is 1.724 x 10-6 ohm-cm.

A. 7.21 x 10-5 ohms

B. 13.8 x 10-6 ohms

C. 5.185 x 10-5 ohms

D. 2.96 x 10-5 ohms

Solution:

37. A generator is rated 100 MW. 13.8 kv and 90% power factor. The ratio of the effective resistance to ohmic resistance is 1.5. The ohmic resistance is obtained by connecting two terminals to a dc source. The current and voltage are 87.6 amperes and 6 volts respectively. What is the effective resistance per phase?

A. 0.0513 ohm

B. 0.0685 ohm

C. 0.342 ohm

D. 0.0617 ohm

Solution:

38. A certain capacitor is charged at 48 volts after which its-stored energy is 5.76 x 10-2 joules. What is the capacitance of the capacitor?

Solution:

39. A 13.8 kV/ 480 V, 10 MVA three phase transformer has 5% impedance, What is the impedance in ohms referred to the primary?

A. 0.952 ohm

B. 0.03 ohm

C. 5.125 ohm

D. 9.01 ohm

Solution:

40. A 50 HP three phase motor, rated 220 V, 75% power factor has 6 poles. The slip at full load is 3%. What is the frequency of the rotor current at full toad?

A. 1.8 Hz

B. 60 Hz

C. 5.4 Hz

D. 58.2 Hz

Solution:

41. A magnetomotive force is supplied by a current of one ampere through 100 turns. The magnetic circuit consists of a steel core of 1000 permeability, 10 cm long and 4 sq. cm. area: and an air gap one cm long. What is the field intensity at the air gap?

A. 12.250 oersted

B. 497.66 oersted

C. 100.53 oersted

D. 124.4 oersted

Solution:

42. The illumination of n room is being designed. The data are as follows.

Room length = 30 ft                                    Room width = 20 ft

Coefficient of utilization = 0.6                  Maintenance factor = 70%

Required foot-candles = 50                       Lumens per lamp = 3300

Watts per lamp = 53                                   Voltage = 220

Power factor = 75

What is the total current of the lamps required to satisfy the requirement?

A. 21 amperes

B. 15 amperes

C. 7 amperes

D. 25 amperes

Solution:

43. In the list below, which one is not a type of present day nuclear power plant?

A. Boiling water reactor

B. Low pressure reactor

C. Fusion-fission reactor

D. Fast breeder reactor

Solution:

44. The sequence components of phase a current are:

zero sequence current = 0.47 +j1.49

positive sequence current 18.4 cis (-31.6°)

negative sequence current = 3.23 cis 168.2°

Determine the phase C current.

A. 17.5 cis 91°

B. 18 cis 215°

C. 22.5 cis 82°

D. 15 cis 100°

Solution:

45. In a short circuit study, the positive, negative and zero sequence impedances are 0.25 p.u., 0.25 p.u. and 0.3 p.u. respectively. The base MVA is 100. Determine the fault current for a three phase fault at the 115 kV level.

A. 3000 amperes

B. 2000 amperes

C. 2500 amperes

D. 3500 amperes

Solution:

46. Three impedances each of 10 + j5 ohms are connected delta on a balance three phase source. If the equation of phase voltage is Vm, = 120 sin ωt, what is the equation of the current through the impedance connected across phase A and B?

A. 20.02 sin (ωt – 22°)

B. 18.59 sin (ωt + 3.44°)

C. 16.21 sin (ωt + 56.56°)

D. 21.32 sin (ωt – 8.15°)

Solution:

47. A four pole dc generator with lap winding has 48 slots and 4 elements per slot. How many coils does it have?

A. 48

B. 384

C. 192

D. 96

Solution:

48. A 50 MVA, 33kV/11 kV, three phase, wye-delta, connected transformer has a 3% impedance. What is the percent impedance at 100 MVA base and 34.5 kV base?

A. 1.639%

B. 5.49%

C. 5.74%

D. 6.56%

Solution:

49. A short 230 kV transmission line has an impedance of 5 cis 78 ohms. The sending end power is 100 MW at 230 kV and 85% power factor. What is the voltage at the other end?

A. 225.4 kV

B. 226.3 kV

C. 223.2 kV

D. 228.2 kV

Solution:

50. Three resistors of 10, 15 and 20 ohm each are connected in parallel. What is the total conductance?

A. 0.217 mhos

B. 3.41 mhos

C. 4.62 mhos

D. 0.52 mhos

Solution:

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