EE SET 2 Flashcards
The primary of an ideal transformer has 100 turns and the secondary has 600 turns. Then:
A. The power in the primary circuit is less than that in the secondary circuit
B. The voltage in the two circuits are the same
C. The primary current is six times the secondary current
D. The currents in the two circuit are the same
The primary current is six times the secondary current
During a short circuit test, the iron losses are negligible because:
A. current is high
B. power factor is low
C. none of these
D. mutual flux is small
mutual flux is small
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:
A. zero
B. up to the left edge and from right to left along the top edge
C. clockwise
D. counterclockwise
clockwise
Which of the following will you connect to make a galvanometer into an ammeter?
A. a low resistance in parallel
B. a high resistance in parallel
C. a low resistance in series
D. a high resistance in series
a low resistance in parallel
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:
A. d/3
B. d/9
C. 3d
D. 9d
3d
The following are type of AC motor staters except one
A. Reactance starter
B. Wye - delta starter
C. Capacitance starter
D. Across the line starter
Across the line starter
The relay that is used to prevent motorizing of a generator is a
A. series power relay
B. forward power relay
C. shunt power relay
D. reverse power relay
reverse power relay
The coulomb force F, acts on two charges a distance, r, apart. What is F proportional to?
A. 1/r^3
B. r
C. 1/r^2
D. r^2
1/r^2
Positive charge is distributed uniformly throughout a non-conducting sphere. The highest electric potential occurs
A. at the surface
B. far from the sphere
C. just outside the surface
D. at the center
at the center
By increasing the transmission voltage double of its original value, the same power can be dispatch keeping the line loss
A. Double the original value
B. Half of the original value
C. Equal to its original value
D. One-fourth the original value
One-fourth the original value
The specific resistance ρ depends upon
A. The area of cross-section and the length of the conductor
B. The nature of the material of the conductor only
C. The material of the conductor, its area of cross-section and length
D. The area of cross-section of the conductor
The nature of the material of the conductor only
In a DC motor, what is the definition of “field resistance”?
A. It is load resistance seen by a generator without considering inductance.
B. It is the resistance of the armature windings plus the load resistance.
C. It is the resistance of the excitation circuit.
D. It is the static resistance of the motor.
It is the resistance of the excitation circuit.
The electrical analog of a spring constant k is:
A. L
B. 1/C
C. C
D. 1/L
1/C
Which of the following protective device operates on the principle of Kirchhoff’s Current Law?
A. Differential Protective Relay
B. Instantaneous Overcurrent Relay
C. AC Time Overcurrent Relay
D. Undercurrent Relay
Differential Protective Relay
1 weber is the same as:
A. 1 T/m
B. 1 V · s
C. 1 T · s
D. 1 V/s
1 V · s
In a transmission line of negligible resistance, the surge impedance will be
A. square root of 1/LC
B. square root of C/L
C. square root of LC
D. square root of L/C
square root of L/C
In the context of the loop and junctions rules for electrical circuits a junction is:
A. where only two wires are joined
B. where three or more wires are joined
C. where a wire is connected to a resistor
D. where a wire is connected to a battery
where three or more wires are joined
For two alternators operating in parallel, if the load shared by one of them is to be increased, its field excitation is
A. to be kept constant but input torque should be decreased
B. to be weakened keeping input torque the same
C. to be kept constant but input torque should be increased
D. to be strengthened keeping input torque the same
to be kept constant but input torque should be increased
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:
A. T/2
B. T/4
C. 2T
D. T
T/2
Which of the following that uses water power is a limited storage power plant?
A. Run-of-River (ROR)
B. Pumped Storage
C. Ocean power
D. Tidal power plant
Pumped Storage
A charged capacitor is being discharged through a resistor. At the end of one time constant the charge has been reduced by (1-1/e) = 63% of its initial value. At the end of two time constants the charge has been reduced by what percent of its initial value?
A. 100%
B. 82%
C. 86%
D. Between 90% and 100%
86%
Which of the following will the effect of the electric shock in the human body depend on?
A. resistance of the line
B. current flowing in the body
C. line power
D. voltage flowing in the body
current flowing in the body
What is the purpose of reactor in short circuit?
A. to increase the current in short circuit
B. to lessen the current in short circuit
C. to open the line in short circuit
D. to decrease the circuit resistance
To lessen the current in short circuit
Which is not a standard distribution voltage in the Philippines?
A. 34.5 kV
B. 13.2 kV
C. 69 kV
D. 13.8 kV
69 kV
What is the instrument often used to check the degree of motor shaft misalignment?
A. Voltmeter
B. Dial Indicator
C. Megaohmmeter
D. Clamp-on Ammeter
Dial Indicator
In sockets, extension cords are protected by means of _________ knot.
A. Clove hitch
B. Sheep shank
C. Western union
D. Underwriters’
Underwriters’
Which of the following shall NOT be excluded in the calculation of reliability standard indices of the distributor asset by the Philippine Distribution Code?
A. Outages that occur on the secondary lines of the distribution system
B. Outages that occur in the transmission line.
C. Outages that occur on the primary lines of the distribution system
D. Planned outages where the customers have been notified at least three (3) days prior to the loss of power.
Outages that occur on the primary lines of the distribution system
The impedance of an RLC series circuit is definitely increased if:
A. R increases
B. L decreases
C. L increases
D. C decreases
R increases
If the per unit impedance is x pu, what is the new per unit impedance when both base power and voltage are doubled
A. 4x
B. x
C. 2x
D. 0.5x
0.5x
Which of the following AC device is used to measure the angle between the voltage and its current?
A. power factor meter
B. reactive meter
C. demand meter
D. phase angle meter
phase angle meter
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:
A. moves to your right
B. moves away from you
C. moves to your left
D. moves toward you
moves toward you
The process of heating electrically non-metallic elements such as plumbers, plastics etc.
A. capacitive
B. induction
C. resistive
D. dielectric
dielectric
An ACSR conductor has (n – 1) layers around its single center strand, the total number of strands will be
A. 3n^2 – 3n + 1
B. 3n^2 – 3n - 1
C. 3n^2 + 3n - 1
D. 3n^2 + 3n + 1
3n^2 – 3n + 1
If a circuit has L closed loops, B branches, and J junctions the number of independent loop equations is:
A. B - J + 1
B. B
C. L
D. B - J
B − J + 1
A car battery is rated at 80 ampere-hour. An ampere-hour is a unit of
A. energy
B. current
C. charge
D. power
charge
The unit of magnetic dipole moment is
A. Amp-m
B. Amp-m^2
C. Amp/m
D. Amp/m^2
Amp-m^2
The tesla is a unit of _________.
A. inductance
B. capacitance
C. magnetic flux density
D. permittivity
magnetic flux density
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.
A. Customer Average Interruption Frequency Index
B. Customer Average Interruption Duration Index
C. System Average Interruption Frequency Index
D. System Average Interruption Duration Index
System Average Interruption Frequency Index
If the magnetic flux through a certain region is changing with time ____________________,
A. a magnetic field must exist at the boundary
B. an emf must exist around the boundary
C. a current must flow around the boundary
D. an electric field must exist at the boundary
an emf must exist around the boundary
A wattmeter method which is suitable to use for unbalanced load is
A. 2-wattmeter method
B. 1-wattmeter method
C. 4-wattmeter method
D. 5-wattmeter method
2-wattmeter method
Which of the following is not included in a basic communication circuit?
A. receiver
B. communication channel
C. antenna
D. transmitter
antenna
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:
A. four times that in 2
B. half that in 2
C. the same as that in 2
D. twice that in 2
half that in 2
Faraday’s law states that an induced emf is proportional to:
A. the rate of change of the electric flux
B. the rate of change of the magnetic flux
C. the rate of change of the electric field
D. the rate of change of the magnetic field
the rate of change of the magnetic flux
Power lost due to alternating magnetization and demagnetization of the core material
A. copper loss
B. eddy current loss
C. rheostat loss
D. hysteresis loss
hysteresis loss
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. a large capacitance
B. a large resistance
C. a large inductance
D. a small capacitance
a large resistance
When the current and voltage are out of phase by 90 degrees, the power is
A. average
B. zero
C. minimum
D. maximum
zero
An unconventional conductor consists of three strands arranged vertically. Find the GMR in terms of radius r of and individual strand.
A. 1.564r
B. 1.864r
C. 1.764r
D. 1.704r
1.704r
A step-down transformer is used to
A. decrease the voltage
B. increase the voltage
C. decrease the power
D. increase the power
decrease the voltage
Which of the following is NOT a property of magnetic field lines?
A. The field is stronger where the lines are closer together.
B. The lines intersect surface of equal intensity at right angles.
C. The lines cross themselves only at right angles.
D. Magnetic field lines have no beginning and no ends.
The lines cross themselves only at right angles.
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:
A. the current in 1 is twice that in 2
B. the potential difference across 1 is half that across 2
C. the current in 1 is half that in 2
D. the potential difference across 1 is twice that across 2
the current in 1 is half that in 2
What is the resistance of an open fuse circuit?
A. 100 ohms standard temperature
B. zero
C. at least 1000 ohms
D. infinity
infinity
The emf of a battery is equal to its terminal potential difference:
A. only when there is no current in the battery
B. only when a large current is in the battery
C. under all conditions
D. only when the battery is being charged
only when there is no current in the battery
The current density is the same on two wires. Wire A has twice the free-electron concentrated of wire B. The drift speed of electron in a is:
A. Four time the of electrons in B
B. One-fourth that of electron in B
C. Half that of electrons in B
D. Twice that of electron in B
Half that of electrons in B
Radio receivers are usually tuned by adjusting the capacitor of an LC circuit. If C = C1 for a frequency of 600 kHz, then for a frequency of 1200 kHz one must adjust C to:
A. 4C1
B. C1/2
C. 2C1
D. C1/4
C1/4
The winding of power transformer usually develops short circuit on account of
A. impulse voltage
B. loose connection
C. mechanical vibration
D. insulation failure
impulse voltage
The magnetic torque exerted on a flat current-carrying loop of wire by a uniform magnetic field B is
A. maximum when the plane of the loop is parallel to B
B. independent of the orientation of the loop
C. dependent on the shape of the loop for a fixed loop area
D. maximum when the plane of the loop is perpendicular to B
maximum when the plane of the loop is parallel to B
What can usually be assumed as the driving or source voltage for fault and voltage calculations in per unit method?
A. 1 p.u.
B. 3 p.u.
C. 10 p.u.
D. 5 p.u.
1 p.u.
What is the maximum number of quarter bends permitted in rigid metal conduits between outlets?
A. 3
B. 5
C. 2
D. 4
4
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?
A. blue alert
B. red alert
C. Yellow alert
D. orange alert
blue alert
An initially uncharged capacitor C is connected in series with resistor R. This combination is then connected to a battery of emf V0. Sufficient time elapses so that a steady state is reached. Which of the following statements is NOT true?
A. The total thermal energy generated by R is independent of V0
B. The total thermal energy generated by R is independent of R
C. The final charge on C is independent of R
D. The time constant is independent of V0
The total thermal energy generated by R is independent of R
A dc series motor connected to alternating current power supply. What will happen?
A. Run on the same efficiency
B. Will not burn
C. Run but with less efficiency
D. Will get burn
Run but with less efficiency
The power factor of incandescent bulb is
A. 0.8 lagging
B. zero
C. unity
D. 0.8 leading
unity
Series capacitors are used to compensate for
A. Improve the line voltage
B. None of these
C. Compensate for line inductive reactance
D. Compensate for line capacitive reactance
Compensate for line inductive reactance
In a purely inductive circuit, the current lags the voltage by:
A. one-half of a cycle
B. one-fourth of a cycle
C. zero
D. three-fourths of a cycle
one-fourth of a cycle
The diversity factor is defined as the
A. Average demand over maximum demand
B. Maximum demand over sum of consumer’s maximum demand
C. Average demand over maximum load on the station
D. Sum of consumers maximum demand over maximum load on the station
Sum of consumers maximum demand over maximum load on the station
Root-mean-square is also called the _______ voltage.
A. maximum
B. average
C. effective
D. peak
effective
The current is zero in a conductor when NO potential difference is applied because
A. the electrons are not moving
B. the electrons are not moving fast enough
C. equal numbers of electrons and protons are moving together
D. for every electron with a given velocity there is another with a velocity of equal magnitude and opposite direction
for every electron with a given velocity there is another with a velocity of equal magnitude and opposite direction
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.
A. 1.6921r
B. 1.7037r
C. 1.3052r
D. 1.3008r
1.6921r
What is/are the main reason/s for using high voltage in the transmission of power in the grid system?
I. to transmit bulk power with minimum line losses
II. Increase system reliability
A. I only
B. either I or II
C. II only
D. both I and II
I only
The units of motional emf are:
A. tesla·meter^2/second
B. volt/second
C. volt/tesla
D. volt·meter/second
tesla·meter^2/second
