EE Mockboard 1 Flashcards by Pauline Peralta

Which of the following relays are used for phase fault on long line?
A. impedance relays
B. reactance relays
C. MHO relays
D. over current relays

impedance relays

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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. the same as that in 2
B. twice that in 2
C. half that in 2
D. four times that in 2

half that in 2

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Overvoltage relay is device number

A. 21
B. 27
C. 52
D. 59

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A transformer has a reactance of 0.04 pu. If the secondary of the transformer is short circuited with the nominal voltage applied to the primary, the symmetrical short circuit current will be
A. 4 times of the full load current
B. 16 times of the full load current
C. 25 times of the full load current
D. 29 times of the full load current

25 times of the full load current

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For constant transmission efficiency, voltage is increased n times, the size of the conductor would be
A. reduced to (1/n^2) times of the original
B. reduced to (1/n) times of the original
C. increased to (n^2) times of the original
D. increased to (n) times of the original

reduced to (1/n^2) times of the original

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Which of the following will you connect to make a galvanometer into an ammeter?
A. a high resistance in parallel
B. a high resistance in series
C. a low resistance in series
D. a low resistance in parallel

Answer: a low resistance in parallel

If a high resistance in series the answer is voltmeter

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In a series circuit, the current is
A. inversely proportional to the resistance
B. variable
C. proportional to the resistance
D. constant

constant

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Which of the following statement is false?

A. RTOS performs tasks in predictable amount of time
B. Windows 98 is RTOS
C. Interrupts are used to develop RTOS
D. Kernel is the one of component of any OS

windows 98 is RTOS

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One primary and one secondary terminal of a two-winding transformer are connected to an ohm-meter instrument. What will be the reading on this instrument?

A. Infinity
B. Zero or infinity
C. Equal to winding resistance
D. Zero

Infinity

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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

A. f/4
B. f
C. 2f
D. f/2

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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?

A. The DC equipment is significantly less expensive.
B. The DC configuration provides high torque and good incremental power at low speeds, and performs equally well at high speeds.
C. Historically, the DC engines configuration has been used. There is no reason to change this.
D. By using the DC equipment, the power factor problems associated with AC equipment are avoided

The DC configuration provides high torque and good incremental power at low speeds, and performs equally well at high speeds.

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The power transmission capacity of the transmission is

A. inversely proportional to the voltage
B. directly proportional to the voltage
C. proportional to the square of the voltage
D. proportional to the cube of the voltage

proportional to the square of the voltage

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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.

A. the first
B. each
C. the last
D. the largest

each

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

A. Double line to ground
B. Three-phase
C. Line to line
D. Line to ground

Three-phase

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The power lost is MORE consider in the design of

A. a motor
B. a generator
C. the feeder
D. the transmission line

Answer: the transmission line

IF the feeder, the answer is voltage regulation

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Four wires meet at a junction. The first carries 4A into the junction, the second carries 5A out of the junction, and the third carries 2A out of the junction. The fourth carries:

A. 7A out of the junction
B. 3A out of the junction
C. 7A into the junction
D. 3A into the junction

3A into the junction solvable

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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 toward you
B. moves away from you
C. moves to your right
D. moves to your left

moves toward you

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Faraday’s law states that an induced emf is proportional to:

A. the rate of change of the magnetic field
B. the rate of change of the electric field
C. the rate of change of the magnetic flux
D. the rate of change of the electric flux

the rate of change of the magnetic flux

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A car battery is rated at 80 ampere-hour. An ampere-hour is a unit of

A. power
B. energy
C. charge
D. current

charge

The rating of a circuit breaker is generally determined on the basis of

A. Line-to-line fault current
B. Symmetrical fault current
C. Single line to ground fault current
D. Double line to ground fault current

symmetrical fault current

Only one of the two devices on a link can transmit; the other can only receive.

A. Half Duplex
B. Full Duplex
C. Simplex
D. Bicomm

Simplex

A disconnecting means shall be located within sight from the motor controller

A. manufacturing rule
B. construction rule
C. wiring design rule
D. installation rule

installation rule

Differential relays are used to protect the transformer against

A. Reverse current
B. Internal faults
C. Overcurrents
D. No voltage

Internal faults

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 perpendicular to B
B. independent of the orientation of the loop
C. maximum when the plane of the loop is parallel to B
D. dependent on the shape of the loop for a ﬁxed loop area

maximum when the plane of the loop is parallel to B

In a purely resistive ac circuit, the current A. lags behind the emf in phase B. leads the emf in phase C. is in phase with the emf D. leads the emf in half the cycle and lags behind it on the other half

is in phase with the emf

The readings of the wattmeter will be same in the two-wattmeter method when A. load in one phases is zero B. power factor is unity C. power factor is 0.50 D. neutral is grounded

power factor is unity

The effect of series capacitor on a transmission line is to improve A. steady state stability B. transient stability C. A and B both D. none of these

steady state stability

Which of the following is a variable renewable source of energy (VRE)? A. Gas turbine plant B. Solar plant C. Coal Plant D. Diesel Plant

Solar plant

Heating effect of current has an undesirable side effect in A. electric oven B. immersion heater C. electric iron D. vacuum cleaner

vacuum cleaner

Two 110-V light bulbs, one “25” and the other “100W”, are connected in series to a 110 V source. Then, which of the following statement is correct with regard to above sentence? A. None of these B. the current in the 100-W bulb is less than that in the 25-W bulb C. Each bulb will have a potential diﬀerence of 55V. D. both bulbs will light with equal brightness

none of these

Current has units of__________. A. coulomb B. ohm C. volt D. coulomb/second

coulomb/second

The boundary of the protection system is determined by the locations of A. voltage transformers B. current transformers C. Protective relays D. circuit breakers

current transformers

What is the equivalent IEEE device number for an under-voltage relay? A. 67 B. 52 C. 27 D. 51

Copper loss of a transformer are determined by means of a/an _____ test. A. open-circuit B. polarity C. short-circuit D. inductive-circuit

short-circuit

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. 1.764r C. 1.704r D. 1.864r

1.704r

Which of the following protective device operates on the principle of Kirchhoff's current law? A. Instantaneous Overcurrent Relay B. Differential Protective Relay C. Undercurrent Relay D. AC Time Overcurrent Relay

Differential Protective Relay

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 C. T/4 D. 2T

T/2 **There is no such thing as T and 2T** *T/4* is for **inductor and current** *T/2* is for **charge, capacitor and voltage**

If R is the distance from a magnetic dipole, then the magnetic field it produces is proportional to: A. R B. 1/R C. R^2 D. 1/R^3

*Answer:* **1/R^3** **Force in conductor** = 1/R **Force between charges or Law of magnetic force** = 1/R^2 **Force in magnetic dipole** = 1/R^3

You are facing a loop of wire which carries a clockwise current of 3.0 A and which surrounds an area of 5.8 x 10-2 m2. The magnetic dipole moment of the loop is: A. 3.0 A • m2, away from you B. 3.0 A • m2, toward you C. 0.17 A • m2, away from you D. 0.17 A • m2, toward you

*Answer:* **0.17 A • m2, away from you** *Walang sinabing parallel kaya hindi magiging toward you + ang **clockwise** means **away from you***

Which of the following protects a cable against mechanical injury during handling and laying? I. Armouring II. Bedding A. I B. II C. Both I and II D. Either I or II

For remote operation, which of the following a circuit breaker must be equipped with? A. Inverse time B. Time-delay C. Very inverse time D. shunt

Shunt

________ diode exhibits variable capacitance that depends on the reverse voltage. A. Gunn B. Varactor C. Hot Carrier D. IMPATT

Varactor

What is the allowable rating for branch overload protection if fuse is used for a hermetic motor compressor with rated load current of 37 A. A. 30 A B. 25 A C. 35 A D. 20 A

35 A *Just multiply 27 by 1.15 = 31.05* *27 not 37*

In an oscillating LC circuit, the total stored energy is U. The maximum energy stored in the capacitor during one cycle is ________. A. U/2 B. U C. U/2pi D. U/pi

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? A. 4I B. 2I C. I D. I/2

2I *I* like **island**