Quiz about PROFESSIONAL ELECTRICAL ENGINEERING

Question 1

In the left-hand rule, thumb always represents direction of the ________.

Accepted Answer

force on conductor

Answer

voltage

Answer

current

Answer

magnetic field

Question 2

A balanced delta connected load has impedances Z₁ = Z₂ = Z₃. What is the per phase equivalent impedance in wye?

Accepted Answer

Z1/3

Answer

3Z1

Answer

2Z1 /3

Answer

Z1

Question 3

The net reactance in an RCL circuit is

Accepted Answer

XL-XC

Answer

XL

Answer

Xc

Answer

XC-XL

Question 4

What is the largest rated room air conditioner unit that may he attached to a 20-ampere branch circuit that also serves other receptacles?

Accepted Answer

16

Answer

10

Answer

12

Answer

15

Question 5

A 60-Hz short transmission line, having R = 0.62 ohms per phase and L = 93.24 mH per phase, supplies a three-phase, wye-connected 100 MW load of 0.90 lagging power factor at 230 kV line-to-line voltage. Determine the voltage regulation of the transmission line?

Accepted Answer

3.55%

Answer

3.75%

Answer

3.20%

Answer

3.42%

Question 6

One-way communications is called

Accepted Answer

Simplex

Answer

Half Duplex

Answer

Full Duplex

Answer

Monocomm

Question 7

In two-wattmeter method of power measurement, the readings of the two wattmeters were

6,717 watts and 2,658 watts, respectively. Find the power factor.

Accepted Answer

0.80

Answer

0.90

Answer

0.70

Answer

0.60

Question 8

An ACSR conductor has seven steel strands, it is surrounded by twenty-four aluminum conductors, it is specified as

Accepted Answer

24/7 ACSR

Answer

31 ACSR

Answer

31/7 ACSR

Answer

7/31 ACSR

Question 9

Transmission voltage level of 1,000 kV is categorized as

Accepted Answer

Extra High Voltage

Answer

Low Voltage

Answer

High Voltage

Answer

Ultra-High Voltage

Question 10

A medium unshaded lamp haungs 8 m directly above the table, To what distance should it be lowered to 20 increase the illumination to 2 times its former value?

Accepted Answer

5.66 m

Answer

2.34 m

Answer

4 m

Answer

4.64 m

Question 11

Electric field lines:

Accepted Answer

are vectors in the direction of the electric field

Answer

are trajectories of a test charge

Answer

form closed loops

Answer

are none of these

Question 12

A 200-N/C electric field is in the positive x direction. The force on an electron in this field is:

Accepted Answer

3.2 x 10^-17 N in the negative x direction

Answer

200 N in the positive x direction

Answer

200 N in the negative x direction

Answer

3.2 x 10^-17 N in the positive x direction

Question 13

A lamp produces an initial illumination of 800 lux over a normally placed screen. If the distance of the lamp from the screen is doubled, what is the new illumination on the screen?

Accepted Answer

200 lux

Answer

100 lux

Answer

300 lux

Answer

400 lux

Question 14

In which type of faults given below, all the 3 components la_o, la₁, and la₂ are equal?

Accepted Answer

Single Line to Ground Fault

Answer

Line to Line Fault

Answer

Double line to ground fault

Answer

Three phase fault

Question 15

A certain wire has resistance R. Another wire, of the same material, has half the length and half the diameter of the first wire. The resistance of the second wire is:

Accepted Answer

2R

Answer

R/4

Answer

R/2

Answer

R

Question 16

What is the minimum ampacity of branch circuit conductor for a hermetic motor whose full- load current is 20 A?

Accepted Answer

25 A

Answer

15 A

Answer

20 A

Answer

30 A

Question 17

A sinusoidal voltage V(t) has an rms value of 100 V. Its maximum value is:

Accepted Answer

141 V

Answer

100 V

Answer

707 V

Answer

70.7 V

Question 18

A magnetizing force of 1,000 AT/m will produce a flux density of ______ in air.

Accepted Answer

1.257 mT

Answer

0.63 T

Answer

0.63 mT

Answer

1.257 T

Question 19

If copper loss of a transformer at 7/8th of full-load is 4,900 W, then what is its full-load

copper loss?

Accepted Answer

6,400 W

Answer

429 W

Answer

5,600 W

Answer

375 W

Question 20

A 3-phase circuit 60 HZ, 230 kV transposed transmission line is composed of two 1,272 MCM 54/19 conductors per phase with horizontal configuration. The bundle conductors are 50 cm in distance while phase spacing between the centers of the bundle is 10 meters. If the GMR of the ACSR conductors is 0.0466 ft., find the inductive reactance in ohm/km/phase of the transmission line?

Accepted Answer

0.3775

Answer

0.3398

Answer

0.3628

Answer

0.3964

Question 21

Which is not a characteristic of an ideal transformer?

Accepted Answer

finite permeability

Answer

no losses

Answer

infinite permeability

Answer

no leakage flux

Question 22

What is the IEEE device function number 50?

Accepted Answer

Instantaneous overcurrent relay

Answer

Differential protective relay

Answer

AC circuit breaker

Answer

AC time overcurrent relay

Question 23

Transformer breaths in when

Accepted Answer

load on it decreases

Answer

none of these

Answer

load on it increases

Answer

load remains constant

Question 24

The color reserved for use in equipment grounding conductor is

Accepted Answer

Green

Answer

Yellow

Answer

White

Answer

Gray

Question 25

An ideal step-up transformer with a power factor of 1.0 is used between a 120 Vrms supply and 10 resistor with the supply at the primary. The turns ratio is 70. What is most nearly the average power dissipated due to resistance R?

Accepted Answer

7.1 MW

Answer

17 W

Answer

84 kW

Answer

29 W

Question 26

A system operates at 220 KVA and 11 kV. Using these quantities as base values, find the base current for the system.

Accepted Answer

20 A

Answer

35 A

Answer

25 A

Answer

30 A

Question 27

For an existing a.c. transmission line the string efficiency is 80%. Now if dc. voltage is supplied for the same set up, the string efficiency will be:

Accepted Answer

100%

Answer

80%

Answer

Less than 80%

Answer

More than 80%

Question 28

The inductance per unit length of an overhead line due to internal flux linkages

Accepted Answer

is independent of the size of conductor and constant

Answer

depends on the current through the conductor

Answer

depends on the size of the conductor

Answer

depends on distance between conductors.

Question 29

High permittivity ceramic is used for capacitors of

Accepted Answer

A few pF to a few hundred $$\mu F$$

Answer

A few nF to a few hundred nF

Answer

A few mF to a few hundred mF

Answer

A few pF to a few hundred pF

Question 30

A certain amount of fuel contains 17 x 10¹⁰ BTU of energy. What is the corresponding energy in Gigacalories?

Accepted Answer

42 800

Answer

47 300

Answer

45 500

Answer

49 400

Question 31

If a tropical storm is going to The Philippine Area of Responsibility (PAR) within 2 hours, what type of alert is to be raised in accordance to the Philippine Grid Code?

Accepted Answer

Blue Alert

Answer

Orange Alert

Answer

Yellow Alert

Answer

Red Alert

Question 32

For any circuit the number of independent equations containing emf's, resistances, and currents equals the number of _______.

Accepted Answer

branches

Answer

junction minus 1

Answer

branches minus 1

Answer

junction

Question 33

Which of the following types of fault uses only the equivalent positive impedance of the circuit in the short-circuit calculation?

Accepted Answer

Three-phase fault

Answer

Line-to-line fault

Answer

Double-line-to-ground fault

Answer

Single-line-to-ground fault

Question 34

A washing machine is, in effect, an R-L circuit. If the machine takes 311 W and 4.5 A from a 155-V source when operating normally. Find its power factor. Troubleshoot:

Accepted Answer

0.60 lagging

Answer

0.75 lagging

Answer

0.65 lagging

Answer

0.70 lagging

Question 35

Which of the following define the meaning of load factor?

Accepted Answer

The ratio of average load to maximum load.

Answer

The ratio of average load to installed capacity.

Answer

The ratio of maximum load to average load.

Answer

The ratio of connected load to maximum load.

Question 36

What is the maximum speed at which a 60 Hz synchronous machine can be operated?

Accepted Answer

3600 rpm

Answer

3400 rpm

Answer

3200 rpm

Answer

3000 rpm

Question 37

Three single-phase transformers rated 25 kVA each are connected in delta delta to supply a balanced load of 75 kVA. One transformer is removed for repair, what is the kVA of each remaining transformer?

Accepted Answer

43.3

Answer

57.7

Answer

50

Answer

34.3

Question 38

The rotor of a 3-phase, 60 Hz, 4-pole inductor motor takes 120 kW at 3 Hz. What is the I induction motor?

rotor speed of the I induction motor?

Accepted Answer

1710 rpm

Answer

1800 rpm

Answer

1810 rpm

Answer

1700 rpm

Question 39

The per phase line loss in a 40 km long transmission line is NOT to exceed 60 kW while it is delivering 100 A per phase. If the resistivity of the conductor material is 1.72 x 10-8 ohm-meter, determine the required conductor diameter.

Accepted Answer

1.2083 cm

Answer

1.2071 cm

Answer

1.1721 cm

Answer

1.2204 cm

Question 40

Two 1 10-V light bulbs, one "25" and the other "IOOW", are connected in series to a 110 V source. Then, which of the following statement is correct with regard to above sentence?

Accepted Answer

None of these

Answer

the current in the 100-W bulb is less than that in the 20-W bulb

Answer

Each bulb will have a potential difference of 55V

Answer

The current in the 100-W bulb is greater than that in the 25-W bulb.

Question 41

The growth rate of the energy consumption in our country is 6.9%. In how many years will the energy be quadrupled?

Accepted Answer

20

Answer

30

Answer

15

Answer

25

Question 42

A single-phase, 10-km transmission line has 16.65 mH total inductance. If the distance between the conductors is 1 m, what is the conductor radius?

Accepted Answer

2 cm

Answer

1 cm

Answer

1.5 cm

Answer

2.5 cm

Question 43

A 2-henry inductor has 120 turns. How many turns must be added to raise its inductance to 3 henry?

Accepted Answer

27 turns

Answer

147 turns

Answer

180 turns

Answer

60 turns

Question 44

An inductor has a value of 44 mH at 60 Hz. What is the inductive susceptance stated as an imaginary number?

Accepted Answer

-j0.06

Answer

j0.06

Answer

-j17

Answer

j17

Question 45

The commonly used light sensor in a modern fax machine is the _________.

Accepted Answer

charge couple device

Answer

liquid crystal display

Answer

photo transistor

Answer

photo tube

Question 46

A collision avoidance radar is designed to detect the presence of vehicles up to a range of 0.50 km. What is the maximum pulse repetition frequency, PRF?

Accepted Answer

300 kHz

Answer

600 kHz

Answer

300 MHz

Answer

600 MHz

Question 47

A small wind generator is designed to generate 50 kW of power at a wind velocity of 25 miles per hour. What is the approximate blade diameter?

Accepted Answer

10.98

Answer

9.98 m

Answer

12.98 m

Answer

11.98

Question 48

A 10-km long, single phase short transmission line has 0.5L600 Q/km impedance. The line supplies a 316.8-kW load at 0.8 power factor lagging. What is the voltage regulation if the receiving end voltage is 3.3 kV?

Accepted Answer

16.94%

Answer

16.74%

Answer

1.67%

Answer

1.69%

Question 49

A generating station has a maximum demand of 1000 MW. The annual load factor is 75% and plant capacity factor is 60%. The reserve capacity is

Accepted Answer

250 MW

Answer

750 MW

Answer

1.25 MW

Answer

1000 MW

Question 50

A substance that changes its electrical resistance When illuminated by light is called:

Accepted Answer

Photoconductive

Answer

Photovoltaic

Answer

Photoelectric

Answer

None of these

Question 51

To adjust the power of the alternator, adjust the ______.

Accepted Answer

Governor

Answer

power factor

Answer

field current

Answer

frequency

Question 52

In a series RC circuit, the voltage across the capacitor and the resistor are 60 v and 80 v respectively. What is the total voltage of the circuit?

Accepted Answer

100v

Answer

120v

Answer

115v

Answer

105v

Question 53

A generator delivers a load through a pair of wires, each of which has a resistance of 0.06 ohm. If the lond voltage and power are 120 v and 4.8 kW, respective what is the generated voltage?

Accepted Answer

124.8 V

Answer

125.5 V

Answer

126.8 V

Answer

123.5 V

Question 54

In a 4-pole, 60 Hz. 200v induction motor having a full-load current of 350 A, torque developed is 700 N-m. What is the approximate speed of the motor?

Accepted Answer

955 rpm

Answer

1100 rpm

Answer

870 rpm

Answer

1250 rpm

Question 55

Three resistances of 4, 9, and 11 ohms are connected in series and then in parallel. Find the effective resistance for series connection.

Accepted Answer

24 ohms

Answer

15 ohms

Answer

20 ohms

Answer

13 ohms

Question 56

A washing machine is, in effect, an KL circuit. If the machine takes 311 Wand 4.5 A form a 115-v source when operating normally. Find its power factor.

Accepted Answer

0.60 lagging

Answer

0.70 lagging

Answer

0.80 lagging

Answer

0.75 lagging

Question 57

When the voltage remains the same, the current will. as the impedance decreases.

I. decrease II. increase

Accepted Answer

II only

Answer

I only

Answer

Both

Answer

Either I or II

Question 58

When electrons build up p sure at one point. it is called _______.

Accepted Answer

current flow

Answer

Ganging

Answer

Impedance

Answer

pressure filing

Question 59

Which of the following type of fault used sequence impedance of the circuit in the only the equivalent positive and negative short-circuit calculation?

Accepted Answer

Line to line

Answer

Double line to ground

Answer

Three-phase

Answer

Line to ground

Question 60

A 69 KV three-phase transposed line is composed of one ACSR 336,400 cmil, 26/7 Linnet conductor per phase with a horizontal configuration of D, 5 ft. 023 5 ft and 0,3 = 10 ft. The conductors have a diameter of 0.721 inch an the inductance per phase per kilometer of the line. GMR of 0.0243 ft. Find the inductance per phase per kilometer of the line.

Accepted Answer

1.1116mH/km

Answer

1.0963mH/km

Answer

1.1505mH/km

Answer

1.1233mH/km

Question 61

Based on the Philippine Distribution Code, all users of the distribution system must maintain a certain power factor at the connection point in order to maintain power quality in the system. What power facior should be maintained at the connection point?

Accepted Answer

Not less than 85%

Answer

Not less than 65%

Answer

Not less than 70%

Answer

Not less than 75%

Question 62

The purpose of insulating oil when used on power circuit breaker are the following, EXCEPT:

Accepted Answer

Interrupter

Answer

Coolant

Answer

Quencher

Answer

Insulation

Question 63

What is the total flux emitted of four lamps having an

Accepted Answer

5,026 lm

Answer

1,256 Im

Answer

2,512 Im

Answer

10,052 lm

Question 64

What is the Thevenin's equivalent reactance of a certain electric system rated 20 MVA at 34.5 KV if the available short circuit MVA is 950?

Accepted Answer

2.10%

Answer

1.75%

Answer

2.25%

Answer

1.59%

PROFESSIONAL ELECTRICAL ENGINEERING

100 questions

At time t = 0 the charge on the 50-µF capacitor in an LC circuit is 15 µC and there is no current. If the inductance is 20 mH the maximum current is:

In the left-hand rule, thumb always represents direction of the ________.

Three capacitances C₁= 6 µF, C₂ = 7 µF and C3 = 18 µF are connected in series across a 120 v supply. Find the voltage across C2.

A balanced delta connected load has impedances Z₁ = Z₂ = Z₃. What is the per phase equivalent impedance in wye?

The net reactance in an RCL circuit is

What is the largest rated room air conditioner unit that may he attached to a 20-ampere branch circuit that also serves other receptacles?

A 60-Hz short transmission line, having R = 0.62 ohms per phase and L = 93.24 mH per phase, supplies a three-phase, wye-connected 100 MW load of 0.90 lagging power factor at 230 kV line-to-line voltage. Determine the voltage regulation of the transmission line?

One-way communications is called

In two-wattmeter method of power measurement, the readings of the two wattmeters were
6,717 watts and 2,658 watts, respectively. Find the power factor.

An ACSR conductor has seven steel strands, it is surrounded by twenty-four aluminum conductors, it is specified as

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PROFESSIONAL ELECTRICAL ENGINEERING

100 questions

At time t = 0 the charge on the 50-µF capacitor in an LC circuit is 15 µC and there is no current. If the inductance is 20 mH the maximum current is:

In the left-hand rule, thumb always represents direction of the ________.

Three capacitances C₁= 6 µF, C₂ = 7 µF and C3 = 18 µF are connected in series across a 120 v supply. Find the voltage across C2.

A balanced delta connected load has impedances Z1 = Z2 = Z3. What is the per phase equivalent impedance in wye?

The net reactance in an RCL circuit is

What is the largest rated room air conditioner unit that may he attached to a 20-ampere branch circuit that also serves other receptacles?

A 60-Hz short transmission line, having R = 0.62 ohms per phase and L = 93.24 mH per phase, supplies a three-phase, wye-connected 100 MW load of 0.90 lagging power factor at 230 kV line-to-line voltage. Determine the voltage regulation of the transmission line?

One-way communications is called

In two-wattmeter method of power measurement, the readings of the two wattmeters were6,717 watts and 2,658 watts, respectively. Find the power factor.

An ACSR conductor has seven steel strands, it is surrounded by twenty-four aluminum conductors, it is specified as

Create a free account and access millions of resources

Similar Resources on Wayground

Popular Resources on Wayground

Discover more resources for Mathematics

A balanced delta connected load has impedances Z₁ = Z₂ = Z₃. What is the per phase equivalent impedance in wye?

In two-wattmeter method of power measurement, the readings of the two wattmeters were
6,717 watts and 2,658 watts, respectively. Find the power factor.