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WorksheetsEE Coaching Set 1
Total questions: 150
Worksheet time: 1hrs 15mins
A charged capacitor and an inductor are connected in series. At time t = 0 the current is zero, but the capacitor is charged. If T is the period of the resulting oscillations, the next time after t = 0 that the energy stored in the electric field of the capacitor is a maximum is:
T /2
T /4
2 T
T
Which of the following that uses water power is a limited storage power plant?
Pumped Storage
Run-of-River (ROR)
ocean power
Tidal power plant
Power lost due to alternating magnetization and demagnetization of the core material
rheostat loss
hysteresis loss
eddy current loss
copper loss
The units of motional emf are:
volt·meter/second
tesla·meter^2/
second
volt/second
volt/tesla
An unconventional conductor consists of three strands arranged vertically. Find the GMR in terms of radius r of and individual strand.
1.764r
1.864r
1.704r
1.564r
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?
105 v
100 v
115 v
120 v
Two identical batteries, each with an emf of 18 V and an internal resistance of 1 Ω, are wired in parallel by connecting their positive terminals together and connecting their negative terminals together. The combination is then wired across a 4-Ω resistor. The current in the 4-Ω resistor is:
4.0 A
2.0 A
1.0 A
3.6 A
A 3-Ω and a 1.5-Ω resistor are wired in parallel and the combination is wired in series to a 4-Ω resistor and a 10-V emf device. The potential difference across the 3-Ω resistor is:
10 V
6.0 V
8.0 V
2.0 V
A transformer has a 3% resistance 5.5% reactance drop. Find the voltage regulation at full-load 0.8 power factor lagging.
3.2%
7.5%
2.3%
5.7%
A series circuit consists of a 20 Ω resistor, a 0.20 H inductor, and 50 microfarad capacitor. If a variable frequency 120 V source is connected across its terminal, what is the resonant frequency in Hz?
55
50
45
40
Which of the following motors is generally used in toys?
Two-value capacitor motor
Shaded-pole motor
Reluctance motor
Hysteresis motor
Which of the following will you connect to make a galvanometer into an ammeter?
a high resistance in series
a low resistance in parallel
a low resistance in series
a high resistance in parallel
The impedance of an RLC series circuit is definitely increased if:
R increases
C decreases
L increases
L decreases
Two parallel wires, 4 cm apart, carry currents of 2 A and 4 A respectively, in the same direction. The force per unit length in N/m of one wire on the other is:
4 × 10−5, attractive
4 × 10−5, repulsive
1 × 10−3, attractive
1 × 10−3, repulsive
Root-mean-square is also called the _______ voltage.
maximum
peak
average
effective
The power transmission capacity of the transmission is
proportional to the cube of the voltage
inversely proportional to the voltage
directly proportional to the voltage
proportional to the square of the voltage
Which of the following cannot have a single unit of 100 MW?
Steam power plant
Nuclear power plant
Diesel power plant
Hydro power plant
Four wires meet at a junction. The first carries 4 A into the junction, the second carries 5 A out of the junction, and the third carries 2 A out of the junction. The fourth carries:
3 A out of the junction
7 A into the junction
7 A out of the junction
3 A into the junction
In a series circuit, the current is
inversely proportional to the resistance
variable
constant
proportional to the resistance
Four 20-Ω resistors are connected in parallel and the combination is connected to a 20-V emf device. The current in the device is:
4
5
0.25
1
RA 7832 concerns on
pilferage of electrical energy
pilferage of electricity and electrical materials
pilferage of electricity, theft of transmission materials and rationalizing of system loss
pilferage of electricity, theft of transmission materials and capping of system loss
A single-circuit three-phase transposed transmission line is composed of four ACSR 1,272,000-cmil conductors per phase with horizontal configuration D12 = 14 m, D23 = 45.93 ft, and D13 = 28 m. The bundle spacing is 45 cm. If the conductor have a diameter of 1.382 in., what is the capacitance per phase per kilometer of the line?
0.0135 microF/km
0.0119 microF/km
0.0127 microF/km
0.0150 microF/km
The resistance of resistor 1 is twice the resistance of resistor 2. The two are connected in parallel and a potential difference is maintained across the combination. Then:
the potential difference across 1 is half that across 2
the potential difference across 1 is twice that across 2
the current in 1 is twice that in 2
the current in 1 is half that in 2
In a purely inductive circuit, the current lags the voltage by:
one-fourth of a cycle
zero
three-fourths of a cycle
one-half of a cycle
The tesla is a unit of _________.
inductance
magnetic flux density
capacitance
permittivity
If the armature of an eight-pole machine were wound with a simplex wave winding, how many parallel path would be there?
4
2
8
6
The trip coil of a circuit breaker is connected through a CT of ratio 50:1. If the normal line current is 160 A and circuit breaker is to operate at 125% normal, the trip mechanism should be set to operate at trip current of ___ A.
4
4.8
3.2
6
What is the maximum speed at which a 60 Hz synchronous machine can be operated?
3200 rpm
3000 rpm
3600 rpm
3400 rpm
A light source emits 500 lux when placed 2.86 meters away from a surface, what is the illumination, when the same light souce is placed 1.75 meters away?
817
306
1336
187
Which of the following type of fault used only the equivalent positive and negative sequence impedance of the circuit in the short-circuit calculation?
Line to line
Line to ground
Double line to ground
Three-phase
Resistor 1 has twice the resistance of resistor 2. The two are connected in parallel and a potential difference is maintained across the combination. The rate of thermal energy generation in 1 is:
four times that in 2
twice that in 2
the same as that in 2
half that in 2
21 is the device function number for this relay.
Overvoltage relay
Directional power relay
Undervoltage relay
Distance relay
For any circuit the number of independent equations containing emf’s, resistances, and currents equals:
the number of branches
the number of junctions
the number of branches minus 1
the number of junctions minus 1
Current has units of
ohm
volt
coulomb
coulomb/second
Faraday’s law states that an induced emf is proportional to:
the rate of change of the electric flux
the rate of change of the magnetic flux
the rate of change of the magnetic field
the rate of change of the electric field
Which of the following AC device is used to measure the angle between the voltage and its current?
phase angle meter
power factor meter
demand meter
reactive meter
What is the equivalent of 1 + a + a^2?
0
-1
1
1 + j
The undervoltage relays are usually used for what protection of the electrical equipment?
bus-bar protection
transformer protection
feeder protection
motor protection
The curve representing Ohm’s law is
sine function
linear
parabola
a hyperbola
The magnetic torque exerted on a flat current-carrying loop of wire by a uniform magnetic field B is
dependent on the shape of the loop for a fixed loop area
maximum when the plane of the loop is perpendicular to B
independent of the orientation of the loop
maximum when the plane of the loop is parallel to B
What is ACSR conductor stand for?
Aluminum Cable Stranded Reinforced
Aluminum Cable Steel Reinforced
Anodized Core Steel Reinforced
All conductors Surface Treated and Realigned
The emf of a battery is equal to its terminal potential difference:
only when a large current is in the battery
only when there is no current in the battery
only when the battery is being charged
under all conditions
A 3-Ω and a 1.5-Ω resistor are wired in parallel and the combination is wired in series to a 4-Ω resistor and a 10-V emf device. The current in the 3-Ω resistor is:
0.33 A
2.0 A
3.3 A
0.67 A
The net reactance in a series RLC circuit is
XC + XL
XL
XC
XL – XC
A 115 kV three-phase transposed transmission line is composed of 2-ACSR 336,000 cml, 30/7 Oriole conductors per phase with horizontal configuration: D12 = 7 ft, D23 = 7ft, D13 = 14 ft. The line spacing is measured from the center of the bundled conductors. The distance between the conductors of the bundle is 6 inches. The conductors have a diameter of 0.741 inch and a GMR of 0.02255 ft. Find the capacitance per phase for 20 km of the line in microfarads.
0.1300
0.2889
0.2609
0.2719
Evaluate aj + 1
0.5 + 0.134i
0.5 - 0.134i
0.134 + 0.5i
0.134 - 0.5i
When the current and voltage are out of phase by 90 degrees, the power is
maximum
Average
minimum
zero
Two identical coupled coils have an equivalent inductance of 80 mH when connected series aiding, and 35 mH in series opposing. What is the value of the coefficient of coupling k?
0.139
0.391
0.319
0.913
One KWHR is equal to _________ BTU.
3600
1000
3413
360
In the design of electrical power systems, the IEEE device numbers identify features of a protective device such as relay or circuit breaker. Which of the following is the device number for the ac circuit breaker?
52
60
50
72
The terminal voltage of a battery is 11.8 V when delivering 20 W of power to an external load resistor R. If the battery has an emf of 15 V, find the internal resistance of the battery.
1.96 ohm
1.89 ohm
1.75 ohm
1.68 ohm
Which of the following is NOT a property of magnetic field lines?
The lines cross themselves only at right angles.
The lines intersect surface of equal intensity at right angles.
Magnetic field lines have no beginning and no ends.
The field is stronger where the lines are closer together.
A transformer rated at a maximum of 50 kVA supplies a 25 kW load at power factor 75% lagging. How many kW additional load may be added at unity power factor without exceeding the transformer rating?
25
29
24
20
Copper loss of a transformer are determined by means of a/an __________ test.
open-circuit
inductive-circuit
short-circuit
polarity
Red, red, orange, silver indicates a resistance of
22 kΩ, ±10%
22 Ω, ±5%
2.2 kΩ, ±10%
220 Ω, ±5%
A certain ammeter has an internal resistance of 1Ωand a range from 0 to 50 mA. To make its range from 0 to 5 A, use:
a resistance of 1/99Ω in parallel
series resistance of 99Ω
a resistance of 99Ω in parallel
a resistance of 1/1000Ω in parallel
A total resistance of 3.0 Ω is to be produced by combining an unknown resistor R with a 12 Ω resistor. What is the value of R and how is it to be connected to the 12 Ω resistor?
2.4 Ω, parallel
4.0 Ω, parallel
4.0 Ω, series
2.4 Ω, series
When the service consists of a multiple of individual disconnecting means for grounded system, the main bonding jumper is required to be located in ____ disconnecting mean/s.
the largest
each
the first
the last
The rapid exponential decay in just a few cycles of the charge on the plates of capacitor in an RLC circuit might be due to:
a large resistance
a large inductance
a small capacitance
a large capacitance
A 30-Cd standard light source is compared with a lamp of unknown intensity using a grease-spot photometer. The two light sources are placed 1 m apart, and the grease spot is moved toward the standard light. When the grease spot is 25 cm from the standard light source, the illumination is equal on both sides. Where should the grease spot be placed for the illumination by the unknown light source to be exactly twice the illumination of the standard source?
32 cm from standard
18 cm from standard
82 cm from standard
68 cm from standard
A certain capacitor, in series with a 720-ō resistor, is being charged. At the end of 10 ms its charge is half the final value. The capacitance is about:
14 ÍF
7.2 ÍF
20 ÍF
9.6 ÍF
A certain voltmeter has an internal resistance of 10k-o and a range from 0 to 100 V. To give it a range from 0 to 1000 V, one should connect:
100k-o in parallel
90k-o in parallel
100k-o in series
90k-o in series
A step-down transformer is used to
decrease the power
decrease the voltage
increase the voltage
increase the power
In a DC motor, what is the definition of “field resistance”?
It is load resistance seen by a generator without considering inductance.
It is the resistance of the excitation circuit.
It is the static resistance of the motor.
It is the resistance of the armature windings plus the load resistance.
A 3-phase motor is rated for 50A. What is the minimum inverse time delay circuit breaker rating?
100 A
75 A
250 A
125 A
A coil of wire having a value of 10 + j16 ohms is connected in series with a capacitive reactance XC, and this series combination is then connected in parallel with a resistor R. If the equivalent impedance of the circuit is 8 + j0 ohms, what is the value of XC in ohm/s?
18
16
5
10
A generator delivers a load through a pair of wires, each of which has a resistance of 0.06 ohm. If the load voltage and power are 120 v and 4.8 kW, respectively, what is the generated voltage?
126.8 v
125.5 v
124.8 v
123.5 v
A square loop of wire lies in the plane of the page. A decreasing magnetic field is directed into the page. The induced current in the loop is:
zero
up the left edge and from right to left along the top edge
counterclockwise
clockwise
The unit of magnetic dipole moment is
Amp/m^2
Amp/m
Amp-m^2
Amp-m
Which of the following statement is false?
Windows 98 is RTOS
RTOS performs tasks in predictable amount of time
Kernel is the one of component of any OS
Interrupts are used to develop RTOS
For two alternators operating in parallel, if the load shared by one of them is to be increased, its field excitation is
to be kept constant but input torque should be increased
to be weakened keeping input torque the same
to be strengthened keeping input torque the same
to be kept constant but input torque should be decreased
The readings of the wattmeter will be same in the two-wattmeter method when
power factor is 0.50
load in one phases is zero
power factor is unity
neutral is grounded
What is the maximum full-load current for a window air conditioner connected on a 20-ampere branch circuit that supplies other loads?
15
12
16
10
The current is zero in a conductor when NO potential difference is applied because
equal numbers of electrons and protons are moving together
the electrons are not moving fast enough
for every electron with a given velocity there is another with a velocity of equal magnitude and opposite direction
the electrons are not moving
A stationary conducting loop with internal resistance of 0.50 ohm is placed in a time-varying magnetic field. When the loop is closed, a current of 5 A flows through it. What will the current be if the loop is opened to create a small gap and a 2-ohm resistor is connected across its open ends?
2 A
4 A
3 A
1 A
Nine identical wires, each of diameter d and length L, are connected in series. The combination has the same resistance as a single similar wire of length L but whose diameter is:
d/9
9d
3d
d/3
It is defined as the total number of sustained Customer power Interruptions within a given period divided by the total number of Customers served within the same period.
Customer Average Interruption Frequency Index
System Average Interruption Frequency Index
Customer Average Interruption Duration Index
System Average Interruption Duration Index
Which of the following is a variable renewable source of energy (VRE)?
Solar plant
Coal Plant
Gas turbine plant
Diesel Plant
If a tropical storm is going to the Philippine Area of Responsibility (PAR) within 24 hours what type of alert is to be raised in accordance to the Philippine Grid Code?
Yellow Alert
Blue Alert
Red Alert
Orange Alert
An ACSR conductor has (n – 1) layers around its single center strand, the total number of strands will be
3n^2 – 3n + 1
3n^2 + 3n + 1
3n^2 – 3n – 1
3n^2 + 3n – 1
Four 20-Ω resistors are connected in series and the combination is connected to a 20-V emf device. The potential difference across any one of the resistors is:
1 V
4 V
5 V
20 V
Which of the following statement is false?
RTOS performs tasks in predictable amount of time
Windows 98 is RTOS
Kernel is the one of component of any OS
Interrupts are used to develop RTOS
A conductor has four identical strands arranged in diamond configuration. Find the GMR of the conductor in terms of the radius r of each strand.
1.6921r
1.3052r
1.7037r
1.3008r
R-rate fuses are designed to interrupt
low fault currents only
high fault currents only
high overload currents only
both high overload and fault currents
Two resistors are connected in parallel across a potential difference. The resistance of resistor A is twice that of resistor B. If the current carried by resistor A is I, then what is the current carried by B?
I/2
2I
4I
I
A current is clockwise around the outside edge of this page and a uniform magnetic field is directed parallel to the page, from left to right. If the magnetic force is the only force acting on the page, the page will turn so the right edge:
moves to your left
moves toward you
moves to your right
moves away from you
The color reserved for use in equipment grounding conductor is
Yellow
White
Green
Gray
The reactance in ohms of a 35-µF capacitor connected to a 400-Hz generator is:
11
0.088
0
0.014
A small wind generator is designed to generate 75 kW of power at a wind velocity of 30 mi/hr. What is the approximate blade diameter of the wind generator in ft?
37.3
33.6
35.4
31.9
What is the equivalent IEEE device number for an under-voltage relay?
67
52
51
27
In the context of the loop and junctions rules for electrical circuits a junction is:
where only two wires are joined
where a wire is connected to a battery
where three or more wires are joined
where a wire is connected to a resistor
If a circuit has L closed loops, B branches, and J junctions the number of independent loop equations is:
L
B − J + 1
B − J
B
The value of inductance per conductor in three phase line is ______ times the loop inductance for single phase lines.
2
1
1/3
1/2
An induction motor with 8 poles, 60 Hz is operated with a slip of 3%. Calculate the rotor speed.
1,684
1,024
873
927
A loop of wire carrying a current of 2 A is in the shape of a right triangle with two equal sides, each 15 cm long. A 0.70 T uniform field is parallel to the hypotenuse. What is the resultant magnetic force on the two equal sides?
Zero
0.41 N
0.31 N
0.21 N
What is the instrument often used to check the degree of motor shaft misalignment?
Megohmmeter
Clamp-on Ammeter
Voltmeter
Dial Indicator
A 50 cm long conductor is moved in a field of density 1 Wb/m^2 at a velocity of 30 m/s. What is the emf induced if the motion is perpendicular to the field?
150 v
0.15 v
15 v
1.5 v
Positive charge is distributed uniformly throughout a non-conducting sphere. The highest electric potential occurs
at the surface
just outside the surface
at the center
far from the sphere
As a loop of wire with a resistance of 10 Ω moves in a non-uniform magnetic field, it loses kinetic energy at a uniform rate of 5 mJ/s. The induced emf in the loop:
is 0.2 V
is 0.28 V
is 0
is 2 V
A capacitor in an LC oscillator has a maximum potential difference of 15V and a maximum energy of 360uJ. At a certain instant the energy in the capacitor is 40uJ. At that instant what is the potential difference across the capacitor?
15 V
25 V
10 V
5 V
AC system has the following disadvantages over DC system.
skin effect exists
charging current exists
proximity effect exists
line regulation is more
In a 12-V battery supplies 10 A, find the amount of energy in kJ delivered in 1 hour.
120
432
216
324
Nine identical wires, each of diameter d and length L, are connected in parallel. The combination has the same resistance as a single similar wire of length L but whose diameter is:
9d
d/3
d/9
3d
The curve representing Ohm’s law is
parabola
a hyperbola
sine function
linear
1 weber is the same as:
1 V · s
1 T/m
1 T · s
1 V/s
What can usually be assumed as the driving or source voltage for fault and voltage calculations in per unit method?
1 p.u.
10 p.u.
5 p.u.
3 p.u.
Which of the following shall NOT be excluded in the calculation of reliability standard indices of the distributor asset by the Philippine Distribution Code?
Outages that occur on the primary lines of the distribution system
Outages that occur on the secondary lines of the distribution system
Planned outages where the customers have been notified at least three (3) days prior to the loss of power.
Outages that occur in the transmission line.
If the magnetic flux through a certain region is changing with time ____________________,
a current must flow around the boundary
an electric field must exist at the boundary
an emf must exist around the boundary
a magnetic field must exist at the boundary
Only one of the two devices on a link can transmit; the other can only receive.
Simplex
Bicomm
Full Duplex
Half Duplex
The specific resistance ρ depends upon
The area of cross-section and the length of the conductor
The material of the conductor, its area of cross-section and length
The area of cross-section of the conductor
The nature of the material of the conductor only
The resistance of a rod does NOT depend on ____________.
its material
its length
its temperature
the shape of its cross-sectional area
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?
57.7
34.3
43.3
50
Modern locomotives are powered by DC motors driven by DC generators. Those are, in turn, driven by diesel engines. Which of the following is the reason for using such a configuration instead of AC generator-motor sets?
Historically, the DC engines configuration has been used. There is no reason to change this.
By using the DC equipment, the power factor problems associated with AC equipment are avoided.
The DC equipment is significantly less expensive.
The DC configuration provides high torque and good incremental power at low speeds, and performs equally well at high speeds.
An area of 0.3 square meter is to be illuminated by a lamp at a level of 600 lux. What is the total luminous flux emitted by the lamp?
160 lm
180 lm
190 lm
170 lm
Four 20-Ω resistors are connected in series and the combination is connected to a 20-V emf device. The potential difference across any one of the resistors is:
1 V
20 V
4 V
5 V
The relay that is used to prevent motorizing of a generator is a
series power relay
shunt power relay
forward power relay
reverse power relay
An LC series circuit with an inductance L and a capacitor C has an oscillation frequency of f. Two inductors, each with inductance L, and two capacitors, each with capacitance C, are all wired in series and the circuit is completed. The oscillation frequency is
2f
f
f/2
f/4
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 motor?
955 rpm
1100 rpm
1250 rpm
870 rpm
A car battery is rated at 80 ampere-hour. An ampere-hour is a unit of
energy
current
power
charge
Which of the following cannot have a single unit of 100 MW?
Nuclear power plant
Hydro power plant
Diesel power plant
Steam power plant
In an oscillating LC circuit, the total stored energy is U. The maximum energy stored in the capacitor during one cycle is _____,
U
U/π
U/2π
U/2
Which of the following will the effect of the electric shock in the human body depend on?
line power
resistance of the line
current flowing in the body
voltage flowing in the body
In an ideal 1 : 8 step-down transformer, the primary power is 10 kW and the secondary current is 25 A. The primary voltage is:
50 V
3200 V
400 V
25,600 V
As a loop of wire with a resistance of 10 Ω moves in a constant non-uniform magnetic field, it loses kinetic energy at a uniform rate of 4.0 mJ/s. The induced current in the loop:
20 mA
10 mA
cannot be calculated from
the given data
30 mA
Zero-sequence current will flow in a transmission line when there is
an overvoltage in the line due to switching
a fault across all three phases
a line to line fault
double line to ground fault
Which is not a standard distribution voltage in the Philippines?
13.8 kV
69 kV
13.2 kV
34.5 kV
What is the maximum number of quarter bends permitted in rigid metal conduits between outlets?
5
2
3
4
A battery with an emf of 24 V is connected to a 6-Ω resistor. As a result, current of 3 A exists in the resistor. The terminal potential difference of the battery is:
6 V
18 V
12 V
0
The magnetic field B inside a long ideal solenoid is independent of:
the current
the core material
the cross-sectional area of the solenoid
the spacing of the windings
The coulomb force F, acts on two charges a distance, r, apart. What is F proportional to?
r^2
1/r^3
r
1/r^2
A permeable substance is one
which can behave as a conductor as well as an insulator
which is a strong magnet
which is a good conductor
through which the magnetic lines of force can pass very easily
Modern locomotives are powered by DC motors driven by DC generators. Those are, in turn, driven by diesel engines. Which of the following is the reason for using such a configuration instead of AC generator-motor sets?
The DC configuration provides high torque and good incremental power at low speeds, and performs equally well at high speeds.
The DC equipment is significantly less expensive.
Historically, the DC engines configuration has been used. There is no reason to change this.
By using the DC equipment, the power factor problems associated with AC equipment are avoided
If the per unit impedance is x pu, what is the new per unit impedance when both base power and voltage are doubled
0.5x
4x
x
2x
The growth rate of the energy consumption in our country is 6.9%. In how many years will the energy consumption be quadrupled?
22 yrs
18 yrs
20 yrs
16 yrs
The power factor of incandescent bulb is
unity
zero
0.8 leading
0.8 lagging
What is the purpose of reactor in short circuit?
To open the line in short circuit
To increase the current in short circuit
To decrease the circuit resistance
To lessen the current in short circuit
The illumination of a surface 3.40 m directly below a light source is 25 lux. Find the intensity of the light source.
289 cd
393 cd
231 cd
347 cd
The total energy in an LC circuit is 5.0 × 10−6 J. If L = 25 mH the maximum current is:
14 mA
28 mA
10 mA
20 mA
An LC circuit has an inductance of 15 mH and a capacitance of 10 µF. At one instant the charge on the capacitor is 25 µC. At that instant the current is changing at the rate of:
1.7 × 10−8 A/s
5.9 × 10−3 A/s
3.8 × 10−2 A/s
170 A/s
Which of the following type of fault that used only the equivalent positive impedance of the circuit in the short-circuit calculation?
Double-line-to-ground fault
Three-phase fault
Single-line-to-ground fault
Line-to-line fault
A single loop of wire with a radius of 7.5 cm rotates about a diameter in a uniform magnetic field of 1.6 T. To produce a maximum emf of 1.0 V, it should rotate at:
35 rad/s
0
2.7 rad/s
5.6 rad/s
For any circuit, the number of independent equations containing emf’s, resistances and currents equals:
the number of junctions minus 1
the number of junctions
the number of branches minus 1
the number of branches
A 120V, 200A single phase is supplied by a source 1000 ft. away through a copper conductor with a diameter of 0.45in. and resistivity of 10.4 Ω-CM/ft. What voltage must the supply be?
140.50V
150.64V
124.05V
118.45V
A charged capacitor and an inductor are connected in series. At time t = 0 the current is zero, but the capacitor is charged. If T is the period of the resulting oscillations, the next time after t = 0 that the charge on the capacitor is a maximum is:
T
T/4
2T
T/2
By increasing the transmission voltage double of its original value, the same power can be dispatch keeping the line loss
Equal to its original value
Half of the original value
One-fourth the original value
Double the original value
We desire to make an LC circuit that oscillates at 100 Hz using an inductance of 2.5 H. We also need a capacitance of:
1 µF
1 F
1 mF
100 µF
A charged capacitor and an inductor are connected in series. At time t = 0 the current is zero, but the capacitor is charged. If T is the period of the resulting oscillations, the next time after t = 0 that the energy stored in the magnetic field of the inductor is a maximum is
2 T
T
T /4
T /2
The electrical analog of a spring constant k is:
1/L
1/C
C
L
What is the purpose of reactor in short circuit?
To open the line in short circuit
To increase the current in short circuit
To lessen the current in short circuit
To decrease the circuit resistance
Which of the following protective device operates on the principle of Kirchhoff’s Current Law?
Instantaneous Overcurrent Relay
Differential Protective Relay
AC Time Overcurrent Relay
Undercurrent Relay
Undercurrent Relay
