August 2013

REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION
AUGUST 2012
PROFESSIONAL ELECTRICAL ENGINEERING SUBJECTS
1. Two impedances C1 and C2 are connected in series across a 240 v

source. If C1 IS 24 µF and the total capacitance is 6µF, find the voltage
across C2.
A. 240 v B. 60 v C. 180 v D. 120 v
Solution:
XCT = 1 = 1
2πfC 2π (60) (6x10-6)
XCT = 442.1 Ω
XCT2 = VT = 240 = 0.54
ZT 442.1
V1 = I1 x Xc1
V1 = (0.54) (2 π (60)(241 x 10−6))

V1 = 59.68
V2 = V T - V1
V2 = 240-59.68
V2 = 180 v
2. Estimate the average power output of a wind turbine having a blade of

diameter 1.7 m if the wind velocity ranges from 10 to 30 meter per hour.
A. 40.2 kW B. 42.2 kW C. 44.2 kW

D. 46.2 kW
GIVEN: P10 = 2.46 x 10-3 (35.1)

(103) = 3,030.7
3.28 ft
d = 10.7 x = 35.1 ft
1nd P30 = 246 x 10-3 (35.12)
(302) =81,830.1
v = 10.30 mph
P = 2.46 x 10-3 (d2) (v3)

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P 10+ P 30 P0 = 42.2 KW
P0 = =
2
3,030.7+81,830.1
2
3. A conductor has a radius of 0.1625 inch. What is the are in circular

mils?
A. 26,406.25 B. 82,957.68 C. 100,000 D.

105,625
GIVEN:
r = 0.1625 sin d = 0.325sin
cm =? d= 32sin x 100 mils/ lin
Solution: d = 325mils
d = 0.1625x2 A= d2 = (325)2 = 105,625
4. If there are seven resistors of 33 kΩ , in each parallel, what is the total

resistance?
A. 363 kΩ B. 3.3 kΩ C. 3 kΩ
D. 16.5 kΩ
5. To reverse the direction of rotation of a three-phase inductor motor, it is

necessary to
A. interchange the three line connections

B. reverse the polarity of the rotary circuit
C. increase the resistance of the rotary circuit
D. interchange any two of the three line connections
6. An unconventional conductor consists of three strand arranged

vertically. Find the GMR in terms of radius r of an individual strand.
A. 1.564 r B. 1.764 r C. 1.704 r D. 1.864 r
7. Transformer are rated in
A. KW B. KV C. KWHR D. KVA
AUGUST 2012
8. A current is given by expression i = 2.5sin ωt + 0.8 sin 3ωt + 0.5sin 5ωt.

What is the rms value of the current?
A. 1.54 A B. 2.6 A C. 2.56A D. 1.89 A
GIVEN:
ί = 2.5 sin wt + 0.8sin 3wt + 0.5 sin 5wt
Solution:
2 2
IRMS = √ (Idc)^2+ ( 5 m ) + ( ℑ1 ) +¿ 2
= √ (c-5)^2 + (0.8)^2 + (0.5)^2/ 2
IRMS = 1.89
9. A capacitor is charged to 250 coulombs for 5 seconds. What is the

currents through capacitor?
A. 25 A B. 50 A C. 500 A D. 1250
GIVEN: Solution:
Q = 250 C Q =It ; I =Q/t
t= 5 sec I = 250 c/5sec = 50A
I =?
10. In a series RL circuit, the inductor current _____ the resistor current.
A. lags B. Lead C. is equal to D. is negative of
11. A 120v dc shunt motor has an armature resistance of 200 mΩ. If the
full-load armature current is 75 A, find the starting resistance needed to
limit the armature starting current to 150% of the full-load value.
A. 0.804 Ω B. 0.822 Ω C. 0.849 Ω D. 0.862 Ω
12. The power factor of incandescent bulb is
A. 0.8 lagging B. 0.8 leading C. unity D. zero

AUGUST 2012
13. The law that induces emf and current always opposes the cause
producing them was discovered by
A. Lenz B. Maxwell C. Faraday D. Ohm
14. An inductor in series with a 5 µF capacitor is connected to supply of 20

v, 796 HZ. What is the inductance needed to make the current 5 A
leading?
A. 0.002 H B. 0.007 H C. 0.004 H D.

0.008 H
GIVEN: Xc =1/ 2πfc = 1/ 2π(796)

(5x10-6)
C = 5µF
Xc = 39.99 Ω
V = 20 v
Z = V/I = 20/5 =4
f= 796HZ
Z= Xl - Xc XL = 2π f L
I=5
4 = XL - 39.99 3599 =
L=? 2π(796)L
Solution" XL = 35.99 L =
0.007 mH
15. A 60 kJ per minute heat is rejected from refrigerator. What is the

power input to the refrigerator if cop is 1.2?
A. 0.633 kw B. 0.733 kw C. 0.833 kw D. 0.933 kw
15. Solution:
COD = pi/ pr
Go kj/min x 1min/x = 1 kj/s = 1000w
1.2 = 1000/x
X = 0.833 kw
AUGUST 2012
16. A 2.400/240 volts transformer is connected Y- . What is the base

voltage of the secondary?
A. 415.69 v B. 240 v C. 135.56 v D. 480 v
2,400/240
PRIMARY =2,400
SECONDARY =240
17. Temperature coefficient of a conductor is defined as the
A. increase in resistance per ohm per degree centigrade
B. increase in resistance per degree centigrade
C. increase in resistance per degree absolute
D. decrease in resistance per ohm per degree centigrade
18. A 400 v series motor working with unsaturated field is taking 60 A and
running at 840 rpm. The total resistance of the motor is 0.1 ohm. At what
speed will the motor run when developing half-full load torque.
A. 1,193 rpm B. 1,202 rpm C. 1,167 rpm D. 1,352 rpm
19. A capacitor is placed in parallel with two inductive loads, one of 20 A

at 30° lagging and another one of 40 A at 60° lagging. What must be the
current in the capacitor so that the total current from the source shall be at
unity power factor?
A. 44.64 A B. 36.84 A C. 48.36 A D. 38.32 A
20. Open conductors run individually as service drops shall be _______.
I. insulted II. bare III. covered
A. I only B. II only C. III only D. either I or II
21. A three-phase short transmission line has a per phase impedance of

0.3 + j0.4 Ω. The receiving end voltage is 6.351 volts per phase and the
voltage regulations is not exceed 5 percent. Calculate the total line loss
when it is supplying maximum power.
AUGUST 2012
A. 212.08 MW B. 7.69 MW C. 122.46 MW D. 40.81 MW
22. A parallel plate capacitor is made of 350 plates, separated by

paraffined paper 0.001cm thick (k=2.5). The effective size of the plate is
50 cm x 30 cm. What is the capacitance of this capacitor?
A. 35 µF B. 70 µF C. 115 µF D. 140
µF
GIVEN: C = Σo Σr / d (n-1)
n = 360 C = (8-8SAx10-18) (2.5)

(50x10-3 x 30x10-
k = 25 == (20x10-2x30x10- 15
)/0.001x10-2 (350-1)
2
)
C = 115 µF
Solution:
23. The percentage overloading of two 20 - KVA transformers when

supplying a balanced 3 ᶲ load of 10 kVA in a V-V bank is ______ percent.
A. 15 B. 57.7 C. 73.2 D. 33.3
24. The power factor of an alternator is determined by its
A. speed B. load C. excitation D. prime mover
25. The pitch factor for 3rd harmonic in an alternator having 18 slots per
pole and colt spam 5/6 of pole pitch is
A. 0.707 B. 0.253 C. 0.966 D. 1
26. A certain power plant has reserve capacity above the peak load of
MW. The annual factors are load factor = 59%, capacity factor = 41% and
use factor 46%. Determine hours per year not in service.
A. 952 hours B. 965 hours
C. 924 hours D. 937 hours
LF
= L/ PL ∆L = LE (PL)
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= 0.59 (PL) -1 ∆L =0.41 (INSTALLED

CAPACITY) -4
INSTALLED CAPACITY =
PL + RESERVED EQUATE 3 TO 4
PL = 1.C -10 -2 ∆L = 0.59 (32.78) -5.9
SUBSTITUTE EQ. 2 IN = 13.44 MW

EQ. 1
PUF YEAR = ∆L IN MW -
∆l =0.59 (INSTALLED HR / INSTALLED
CAPACITY -10) CAPACITY IN MW x N
=0.59 INSTALLED 0.46 = 13.44 x 8768 /32.

CAPACITY -59- 3 78 N
PCF = ∆L / INSTALLED N= 7808 HRS

CAPACITY
LET n = 8760 -7808
= 752 HRS
27. The speed of a synchronous motor
A. reduces as load increases
B. increases as load increases
C. adjusts itself to new equilibrium speed whenever load changes
D. always remains constant
28. A heater wire of length 50 cm and 1 mm 2 in cross-section carries a

current of 2 A when connected across a 2 v battery. What is the resistivity
of the wire?
A. 2 x 10-6 Ω-m B. 2 x 10-5 Ω-m
C. 4 x 10-6 Ω-m D. 4 x 10-5 Ω-m
GIVEN: d = 1x10-3 m2
L = 50 x 10 -2 m I = 2∆
AUGUST 2012
V=2v R = PL/ ∆ = 1 = p(50 x

10-2) / (1x10-3)2
P =?
R = V/ I = 2/2 = 1Ω p = 2 x
Solution: 10-6 Ω-m
29. A string insulator has 4 units. The voltage across the bottom most unit
is 30% of the total voltage. What is the string efficiency?
A. 30% B. 60% C. 75% D. 83.33%
30. When a line to ground faults occurs, the current in a faulted phase is
100 A. What is the zero sequence current in this case?
A. zero B. 33.3 A C. 66.6 A D. 100 A
IF = 35ao Iao = 33.3A
100.3 = 3Iao /3
31. A transmission line has a total series impedance of 40 + j125 ohms

and a total shunt admittance of 10 -3 mho. Determine the constant D of the
line.
A. j0.001 B. 0.9376 + j0.0196
C. 1 + j0.0656 D. 0.001 + j0.0656
32. A six-pole three-phase 440-v, 60 HZ induction motor develops 10-HP

at 1,150 rpm, the power factor being 80% lagging. Stator and core losses
amount to 400 w and 350 w, respectively. Frictional losses amount to 0.5-
hp. Calculate motor line current.
A. 12.24 A B. 12.41 A C. 11.42 A D. 14.64 A
33. The efficiency of thermal power plant is approximately
A. 10% B. 30% C. 60% D. 80%
34. A 6.6 kV Y-connected, 3-phase alternator has a synchronous

reactance of 6 Ω per phase and a negligible resistance. At a certain field
current, the armature is known to induce 5.8 kV per phase. Calculate the
maximum power that can be developed by the alternator at this excitation.
AUGUST 2012
A. 12 MW B. 10 MW C. 9.8 MW D. 11 MV
35. A power plant consumes 3,600 tons of coal per day. If the coal has an
average energy content of 10,000 BTU/lb, what is the plant's power
output? Assume an overall efficiency of 15%.
A. 132 MW B. 130 MW C. 128 MW D. 126 MW
36. The positive, negative, and zero sequence reactances of a 20-MVA,

1302 kV synchronous generator are 0.3 pu, 0.2 pu, nad 0.1 pu,
respectively. The generator is solidly grounded and is not loaded. A line to
ground fault occurs on phase a. Neglecting all the resistances, determine
Ia1.
A. -j5 ou B. -j1.67 pu C. -j2.87 pu D. -j3 pu
Ia1(pu) = 1/ Z1 +Z2+Z3
= 1 / j0.3+j0.2+j0.1
= -j1.67
37. The electromagnetic torque developed in a motor is 150 N-m. If the

field flux is decreased by 20% and armature current is increased by 15%,
find the new electromagnetic torque developed.
A. 138 N-m B. 163 N-m C. 159 N-m D. 104 N-m
38. A 220 v, 3-phase , 4-wire abc system supplies unbalanced wye-

connected resistance of Ra = 10 Ω, Rb = 15 Ω and Rc = 20 Ω. Determine
the total power of the system in watts.
A. 3,495 B. 3,560 C. 3,385 D. 3,895
VØ = 220/√8 = 127.02 v
Pa = VØ/ Ra = 127. 02 2/ 10 = 1,613.33
Pb = VØ/ Rb = 127.02 2 /20 = 1,075.56
Pc = VØ/ Rc = = 127.02 2 /20 = 806.67
Pt= 1,613.33 +1,075.56 +806.67

AUGUST 2012
Pt= 3,495.56
39. A coil of wire of 100 turns enclosing an area of 0.09 m 2 has its plane
perpendicular to a uniform magnetic field of flux density 0.5 T. the coil is
turned to position wherein its plane is parallel to the magnetic field in 0.05
sec. Find the average emf generated in the coil in volts.
A. 15 B. 10 C. 12 D. 9
Ø=ß∆ e = N dd/dt
= (0.5) (0.09) e= 100 (0.045/ 0.5)
Ø = 0.0045 e = 9v
e= 0.0045
40. A 10-hp, 230 v, three-phase Y-connected synchronous motor has a

reactance of 3 ohms per phase a negligible resistance. To what voltage
must the motor be excited to deliver full-load at unity power factor and
90% efficiency?
A. 242 v B. 254 v C. 262 v D. 248 v
41. To a series RLC circuit, a voltage of 10 v is applied. If Q of the coil at

resonant frequency is 20, the voltage across the inductor at resonant
frequency will be.
A. 200 v B. 100 V C. 75 v D. 50 v
Solution:
QFactor = EL / ET
20 = EL/10
EL = 200 V
42. One advantage of distributing the winding in alternator is to
A. Reduce harmonies C. reduce the amount of cooper

B. improves voltage wave from D. decreases the value of the voltage
43. A dc shunt motor running at 1,200 rpm has armature resistance of

0.15 Ω. The current taken by the armature is 60 A when the applied
voltage is 220 v. If the load is increased by 30%, find the variation in the
speed.
AUGUST 2012
44. the capacitance between any conductors of a three-phase, three-

conductor cable is 2 µF. The cable operates at 11 kV line voltage and 50
HZ. What is the charging current through the cable capacitance?
A. 7.98 A B. 3.99 A C. 6.91 A D. 13.82 A
45. The per unit reactance’s of a synchronous generator are X d = 1, Xd1 =

0.35, and xd11 = 0.25. The generator supplies at 1.0 per unit load at 0.8
power factor lagging. Calculate the voltage behind the subs transient
reactance.
A. 1.79 pu B. 1.24 pu C. 1.17 pu D. 1.59 pu
46. A series RLC circuit has a Q of 5 at its resonance frequency of 100

kHZ. Assuming the power dissipation of the circuit is 100 w when drawing
a current of 0.4 A, determine the capacitance C of the circuit.
A. 2.04 nF B. 2.32 nF C. 3.02 nF D. 2.54 nF
GIVEN: Xc
Q=
R
Q=5
F = 100 X 103Hz P 100
P = 10W R = 2 = 2 =156.25
I 0.8
I = 0.8∆ Xc
C =? S= ; Xc = 781.25
156.25
1
Xc = ; 782.25
2 πFC
=
SOLUTION: 1
3
; C=2.04
2 π (100 x 10 )(C)
47. An iron ring of circular cross-section of 5 x 10 -4 m2 has a mean
circumference of 2 m. It has a saw-cut of 2 x 10 -3 m length and is wound
with 800 turns of wire. Determine the exciting current when the flux in the
air gap is 0.5 x 10-3 Wb. Given µr of Iron = 600 and leakage factor is 1.2.
Assume areas of air gap and iron are same.
A. 2.95 A B. 3.95 A C. 4.95 A D. 5.95 A

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48. A 50 hp, 440 v, 60 HZ, 3-phase motor operates at full-load with an

efficiency of 89% and power factor of 0.85 lagging. Determine the
capacitance in µf per phase of wye-connected capacitor bank to be
connected across the motor terminals to improve the power factor to 0.95
lagging.
A. 148 B. 167 C. 188 D. 210
49. Impurities in an electrolyte can cause an internal short circuit condition

called
A. depolarization B. electrolysis C. local action D.

polarization
50. A dc constant voltage source feeds a resistance of 2,000 kΩ in series

with a 5µF capacitor. Find the time taken for the capacitor when the
charge retained will be decayed to 50% of the initial value, the voltage
sourcing being short circuited.
A. 11 B. 12 C. 10 D. 14
51. A resistance of 40 ohms and inductance of 79.6 mH are connected in

parallel across a 240 v, 60 HZ ac supply. Find the total current in
amperes.
A. 11 B. 12 C. 10 D. 14
52. A 230 v, 3-phase source supplies a balanced delta connected in

parallel across a 240 v, 60 HZ ax supply. Find the total current in
amperes.
A. 33.1 B. 39.8 C. 26.5 D. 29.3
SOLUTION:
IL= (√3)Vp = (√3)(230)
Z 8 – j6
IL = 39.8
53. Three unbalanced 3-phase currents are given as follows:

AUGUST 2012
Ia = 10 ∠-30° A , Ib = 0 and Ic = 10 ∠-150° A. Find Ic1-
A. 3.34∠150° A B. 3.34∠-150° A C. 3.34∠210° A D. 3.34∠-

135° A
SOLUTION:
Ia1 = 1 {(Ia+a(Ib)+a2(Ic)}
3
= 1{(10<-30)+(1<120(0)+(1<240)(10))}
3
= 3.34<300∆
IC1= a(Ia1)
=(1<120)(3.34<30)
=3.34<1500A
54. Two straingt parallel wires 2 m long, 3 mm apart carries a current of 8

A in opposite direction. Calculate the force between these conductors.
A. 8.25 x 10-3 N B. 8.75 x 10-3 N
C. 8.33 x 10-3 N D. 8.53 x 10-3 N
SOLUTION:
L
F=(2X10-7) (I1I2) ( )
D
2
F=(2X10-7)(8X8)( )
3 X 10−3
F= 8.53X10-3N
55. A three-phase, 6-pole, 50 HZ, induction motor develops a maximum

torque of 30 N-m at 960 rpm. Calculate the torque produced by the motor
at 6% slip. The rotor resistance per phase is 0.6 Ω.
A. 24.7 N-m B. 25.7 N-m C. 26.7 N-m D. 27.7 N-m
56. The turn-on voltage of a Ge junction diode is ______volt.
A. 0.7 B. 0.3 C. 1 D. 0.1
57. A 40 miles, 60 cycle single phase line consists of two 000 conductors
spaced 5 ft apart. Determine the charging current if the voltage between
wires is 33 kV. The diameter of 000 conductors is 410 mils.
A. 3.92 A B. 2.92 A C. 1.92 A D. 4.92 A

AUGUST 2012
58. A transformer has 4% resistance and 6% reactance drop. Find the

voltage regulation at full load 0.8 p.f lagging.
A. 6.8% B. 5.8% C. 8.8% D. 7.8%
SOLUTION:
%Vr=√(cosθ+(%IR))2+(SINθ+-(21%))2-1
=√(0.8+0.04)2+(SIN(36.87)+(0.06))2-1
=0.068X100
=6.8%
59. A dc motor takes an armature current of 100 A at 230 v. The armature

resistance is 0.03 Ω. The total number of lap connected armature
conductors is 500 and the number of poles is 4. The flux per pole is 0.03
Wb. What is the torque developed by the motor?
A. 242.86 N-m B. 218.93 N-m
C. 238.73 N-m D. 227.54 N-m
GIVEN: SOLUTION:
PZ 0 IA
I=100A P=4 T=? T=
6.283 a
( 4 )( 500 ) ( 0.003 ) (100)
V=230V T=
6.283( 4)
R=0.03Ω T=238.73N-M
Z=500Ω
60. A 0.5 µF capacitor, an 80 mH inductance and a 500-ohm resistor are
connected in parallel across a voltage source of V = 12 -j6 v. Find the
current as a phasor if the angular velocity is 500 rad/sec.
A. 0.333∠ 92° A B. 0.333∠-92° A
C. 0.333∠122° A D. 0.333∠-122° A
61. What is the fourth harmonic of 800 KHZ?
A. 200 KHZ B. 400 KHZ C. 3.20 MHZ D. 4.00 MHZ
F4= F(n) = 800KHZ(4) = 3.2MHZ

AUGUST 2012
62. A mode of communications in which either party can hear while taking,
thus allowing one party to instantly interrupt the other at any time, is called
A. Half simplex B. Half duplex
C. Full simplex D. Dull duplex
63. suppose a cell of 1.5 v delivers 100 mA for 7 hours and 20 minutes,
and the it is replaced. How much energy is supplied during this time?
A. 0.49 Whr B. 1.1 Whr C. 7.33 Whr D. 733 mWhr
20
W(energy) = Pt =(1.5v)(100x10-3)(7+ ) = 1.1Whr
60
64. A device that repeatedly reverse the polarity of a magnetic field in

order to keep a dc motor rotating is known as
A. a solenoid B. an armature coil
C. a commutator D. a field coil
65. Find the cross-sectional area of the core of a 10 turns transformer for
a voltage of 50 v at 50 HZ. The flux density is 0.9 Wb/m 2.
A. 0.025 m2 B. 0.046 m2 C. 0.065 m2 D. 0.085 m2
66. The rotor resistance of an 8-pole, 50 HZ, wound rotor induction motor
is 0.5 Ω per phase. The speed of the motor is 720 rpm at full load.
Determine the external resistance to be connected with the rotor circuit to
reduce the speed to 680 rpm for full-load torque.
A. 0.66625 Ω B. 1.1625 Ω C. 0.5225Ω D. 0.8625 Ω
67. 87 is the device function number assigned by ANSI to this relay;
A. lock out relay C. directional relay

B. undervoltage relay D. differential relay
68. A series RL circuit is connected across a dc source through a switch.

Three milliseconds after the switch is closed, the voltage across the
inductance is 20 v and drops to 5 v after ms. If R = 100 ohms, find L.
Assume at t = 0, i = 0.
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A. 1.59 H B. 1.30 H C. 1.22 H D. 1.25 H
69. A generator rated 600 KVA, 2,400 v, 60 HZ , 3-phase, 6-poles and

wye-connected has 10% synchronous reactance. If a three-phase fault
occurs, what will be the short circuit current?
A. 1, 443 A B. 1,532 A C. 1,435 A D. 1,426 A
GIVEN: SOLUTION:
Sb
Sb=600KVA IF=
¿ 3Vb( Xfu)
600 X 10(3)
V=2,400V I F=
√ 3(2400)(0.1)
f=60HZ IF=1443 A
P=6
IF=?
70. A coil of inductance 8 mH, produces 80 µWb of magnetic flux. Of this

total flux, 60 µWb are linked to a second coil of inductance 2 mH. How
much is the mutual inductance between coils?
A. 2 mH B. 3 mH C. 4 mH D. 5 mH
SOLUTION:
FLUX LINKING L 1∧L 2 60

K= =
L1 80
K=0.75
M=K√L1L2
=0.75√(8X10-3)(2X10-3)
=3X10-3H = 3MH
71. Wind mils in addition to proper gearing is the best driver for
A. dc generator C. inductance generators

B. synchronous generators D. rotary rectifiers
AUGUST 2012
72. A rectangular bus bar is made of aluminum and is 90 cm long, 10 cm

wide and 1 cm thick. If the bus bar current flows along its length, find the
bus bar conductance provided the bus bar conductivity is 3.6 x 10 8 s/m.
A. 0.4 x 106 s B. 0.4 x 105 s C. 0.5 x 106 s D. 0.5 x 105

s
73. An energy source supplies 500 J of energy at 100 v for a certain

period of time. Determine the quantity of charge passed through.
A. 0.2 c B. 50 kc C. 20 c
D. 5 c
SOLUTION:
W=Pt
W 500 J
W=Ivt ∴ Q= = = 5C
V 100V
74. A 220 v, 3-phase supply has a balanced delta connected load with
impedance of 15 + j20 ohms/phase. What is the total real power of the
load in watts?
A. 5,133.3 B. 4,122.5 C. 2,965.6 D. 3,484.8
GIVEN:
V=220
ZØ=15tj20Ω=25<53.13
SOLUTION:
V2
P=3( COSØ)
Z
220
P=3( cos (53.13)¿
25
P=3,484.8W
AUGUST 2012
75. In a 3-phase, 4-wire system, the current in line A has I a1 = 200∠0° A Ia2
=100∠60° A, the current through the neutral conductor is 300∠-60° A. Find
the line current Ib in amperes.
A. 300 ∠ 120° B. 300 ∠-60° C. 300 ∠ 240° D. 100∠-30°
GIVEN: SOLUTION:
Ia1=200<0 In= BIao
Ia2=100<60 Iao=100<-60
In+300<-60 Ib=100<-60+(1<240)(2)(1<120)(100)
Ib=? Ib=300<-120+360
Ib= 300<240
76. Calculate the no-load current taken by a 100 kW, 460 v, shunt motor
assuming the armature and field resistance to remain constant and equal
to 0.03 Ω and 46 Ω, respectively. The efficiency at full load is 88%.
A. 23.5 A B. 24.5 A C. 26.0 A D. 28.0 A
77. A 100 MW hydroelectric station is supplying full load for 10 hrs in a

day . Calculate the volume of water which has been used. Assume
effective head of the water as 200 m and the overall efficiency of the
station as 80%. Assume 1 m3 of water = 1,000 kg.
A. 2,232,435 m3 B. 2,345,456 m3
C. 2,293,560 m3 D. 2,371,402 m3
78. The dc generator used as pilot exciter is
A. series B. Shunt
C. over compound D. flat compound
79. A lead storage battery is rated at 12 volts. If the internal resistance is

0.01 ohm, what is the maximum power that can be delivered to the load?
A. 1,200 w B. 1,800 w C. 3,600 w D. 7,200 w

AUGUST 2012
80. Bundled conductors in EHZ transmission lines results to
A. reduce capacitance C. increase capacitance

B. increase inductance D. increase resistance
81. The per unit impedance of a circuit element is 0.30. If the base KV and
base MVA are halved, then the new value of the per unit impedance of the
circuit element will be,
A. 0.30 B. 0.60 C. 0.0030 D. 0.0060
Vb1 2 Sb 2
Xpu2=Xpu1( ) ( )
Vb2 Sb 1
2 1
Xpu2=0.3 ( )2 ( ¿ ; xpu2=0.60
1 2
82. What should be the turns ratio of a three-phase transformer to

transform 10,000 KVA from 230 KV to 4,160 V if the transformer is to be
connected ∆-Y?
A. 94 B. 96 C. 97 D. 98
83. The input power to a 600-v synchronous motor is measured by means

of a two-method. One wattmeter reads 64 kW and the other reads 36.5
kW. The motor is known to be operating at leading p.f. Determine the line
current drawn.
A. 110 A B. 104 A C. 112 A D. 107 A
SOLUTION:
√ 3(64−36.5)
Ø=tan-1( ¿
(64+ 36.5)
Ø=25.360
W=VLILCOS(30-Ø)
64X103=(600)(IL)COS(30-
25.36)
IL=107
AUGUST 2013
84. A power plant has an overall efficiency of 30%. If this plant can
consume 4,200 kilograms of coal per hour, estimate the total electric
energy produced in one day. Assume the calorific value of the coal being
used is 8,000 kcal per kilogram.
A. 183 MWHR B. 168 MWHR
C. 176 MWHR D. 155 MWHR
85. Four lamps are suspended 6 m above the ground at the corners of a
lawn 4 m on each side. If each lamp emits 250 cd, calculate the
illumination at the center of the lawn.
A. 20.56 lux B. 21.62 lux C. 19.85 lux D. 22.34 lux
d2=(2)2+(2)2+(6)2=44
d=6.63
Et= 4 EACH LAMP
J 250 6
=4( ¿COSØ=4( ¿( ¿
D2 44 6.63
=20.56LUX
86. A 170-mile, 230-kV, 60-HZ, three-phase single-circuit transmission line

uses, a triangular arrangement with 20 ft. 20 ft, and 36 ft spacing
respectively. If the line conductors have a GMR of 0.0217 ft, determine the
capacitive susceptance to neutral per mile.
A. 4.81 x 10-5 mho per mile C. 7.92 x 10-5 mho per mile
B. 12.74 x 10-6 mho per mile D. 2.47 x 10-6 mho per mile
87. The surge impedance of an underground cable is around
A. 50 Ω B. 25 Ω C. 400Ω D. 100 Ω
88. A process equipment contains 100 gallons of water at 25°C. It is

required to bring it to boiling in 10 minutes. The heat loss is estimated to
be 5%. What is the kW rating of the heater?
A. 50.5 kW B. 252 kW C. 125 kW D. 207 kW

AUGUST 2013
89. A 500 MCM ACSR cable has 37 strands. Determine the diameter in
mils of each strand.
A. 116.25 B. 118.34 C. 110.35 D. 120.24
90. A contact device installed at the outlet for the connection of a single
attachment plug.
A. pendant B. switch C. receptacle D. plug
91. An 8-pole lap wound dc generator has 1,000 armature conductors, flux
of 20 mWb per pole and emf generated is 400 v. What is the speed of the
machine?
92. An air cored coil has 500 turns. The mean length of magnetic flux path
is 50 cm and the area of cross-section is 5 x 10 -4 m2. If the exciting current
is 5 A, determine the flux density.
A. 3.1415 x 10-3 T C. 6.283 x 10-3 T

B. 3.1415 x 10-4 T D. 6.283 x 10-4 T
93. In a balanced, 3-phase, wye-connected voltage source with phase

sequence abc, Vab = ∠10° v. Find the phase voltage Von.
A. 230∠-230°v B. 132.8 ∠-80°v
C. 132.8 ∠-140°v D. 132.8 ∠-260°v.
94. When carrier wave is modulated at 100%, its power is increased by

____ percent.
A. 100 B. 150 C. 50 D. 0
95. A certain amount of fuel can produce 10 quads of energy. In how

many days will the fuel be totally consumed if it is used to satisfy a
demand of 1013 BTU/day at a power plant with an overall efficiency of 20
percent?
A. 170 B. 180 C. 190 D. 200
96. Differential relays are installed to protect the equipment against.

AUGUST 2013
A. reverse current B. internal faults C. overcurrent D. no voltage
97. A short 3-phase, 3-wire transmission line has an impedance of 3 + j4

ohms per wire. At the receiving end are connected a 3-phase inductive
load drawing 3,500 kW at 0.8 power factor and line to line voltage of 13,
200-volt and a capacitor bank drawing 150 amperes line current. Calculate
the voltage at the sending end.
A. 13, 808 v B. 13, 718 v C. 13, 758 v D. 13, 658 v
98. A 15 KVA, single-phase distribution transformer has a core and copper

losses at rated condition of 90 w and 300 w, respectively. Determine its
maximum efficiency at 0.707 power factor lagging.
A. 95% B. 96% C. 97% D. 98%
99. A three-phase, 400 v 50 HZ induction motor has a speed of 900 rpm

on full-load. The motor has six poles. How many complete alternations will
the rotor voltage takes per minute?
A. 30 B. 60 C. 300 D. 600
100. This is the porcelain insulator for the end poles;
A. pin B. post C. suspension D. akimbo.

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REGISTERED ELECTRICAL ENGINEERS PRE-BOARD EXAMINATION

1. Two impedances C1 and C2 are connected in series across a 240 v

A. 240 v B. 60 v C. 180 v D. 120 v

V1 = (0.54) (2 π (60)(241 x 10−6))

2. Estimate the average power output of a wind turbine having a blade of

A. 40.2 kW B. 42.2 kW C. 44.2 kW

GIVEN: P10 = 2.46 x 10-3 (35.1)

P = 2.46 x 10-3 (d2) (v3)

3. A conductor has a radius of 0.1625 inch. What is the are in circular

A. 26,406.25 B. 82,957.68 C. 100,000 D.

r = 0.1625 sin d = 0.325sin

cm =? d= 32sin x 100 mils/ lin

d = 0.1625x2 A= d2 = (325)2 = 105,625

4. If there are seven resistors of 33 kΩ , in each parallel, what is the total

5. To reverse the direction of rotation of a three-phase inductor motor, it is

A. interchange the three line connections

6. An unconventional conductor consists of three strand arranged

A. 1.564 r B. 1.764 r C. 1.704 r D. 1.864 r

7. Transformer are rated in

8. A current is given by expression i = 2.5sin ωt + 0.8 sin 3ωt + 0.5sin 5ωt.

A. 1.54 A B. 2.6 A C. 2.56A D. 1.89 A

ί = 2.5 sin wt + 0.8sin 3wt + 0.5 sin 5wt

= √ (c-5)^2 + (0.8)^2 + (0.5)^2/ 2

9. A capacitor is charged to 250 coulombs for 5 seconds. What is the

Q = 250 C Q =It ; I =Q/t

t= 5 sec I = 250 c/5sec = 50A

A. lags B. Lead C. is equal to D. is negative of

A. 0.804 Ω B. 0.822 Ω C. 0.849 Ω D. 0.862 Ω

12. The power factor of incandescent bulb is

A. 0.8 lagging B. 0.8 leading C. unity D. zero

A. Lenz B. Maxwell C. Faraday D. Ohm

14. An inductor in series with a 5 µF capacitor is connected to supply of 20

A. 0.002 H B. 0.007 H C. 0.004 H D.

GIVEN: Xc =1/ 2πfc = 1/ 2π(796)

15. A 60 kJ per minute heat is rejected from refrigerator. What is the

A. 0.633 kw B. 0.733 kw C. 0.833 kw D. 0.933 kw

Go kj/min x 1min/x = 1 kj/s = 1000w

16. A 2.400/240 volts transformer is connected Y- . What is the base

A. 415.69 v B. 240 v C. 135.56 v D. 480 v

17. Temperature coefficient of a conductor is defined as the

A. increase in resistance per ohm per degree centigrade

B. increase in resistance per degree centigrade

C. increase in resistance per degree absolute

D. decrease in resistance per ohm per degree centigrade

A. 1,193 rpm B. 1,202 rpm C. 1,167 rpm D. 1,352 rpm

19. A capacitor is placed in parallel with two inductive loads, one of 20 A

A. 44.64 A B. 36.84 A C. 48.36 A D. 38.32 A

20. Open conductors run individually as service drops shall be _______.

I. insulted II. bare III. covered

A. I only B. II only C. III only D. either I or II

21. A three-phase short transmission line has a per phase impedance of

A. 212.08 MW B. 7.69 MW C. 122.46 MW D. 40.81 MW

22. A parallel plate capacitor is made of 350 plates, separated by

n = 360 C = (8-8SAx10-18) (2.5)

23. The percentage overloading of two 20 - KVA transformers when

A. 15 B. 57.7 C. 73.2 D. 33.3

24. The power factor of an alternator is determined by its

A. speed B. load C. excitation D. prime mover

A. 0.707 B. 0.253 C. 0.966 D. 1