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WorksheetsELECTRICAL ENGINEERS PRE-BOARD EXAMINATION MARCH 2015
Total questions: 33
Worksheet time: 17mins
A material best suited for manufacturing of fuse wire is
Aluminum
Silver
Lead
Copper
In the Fleming’s left hand rule, thumb always represents
voltage
direction of force on conductor
current
magnetic field
The net reactance in a series RLC circuit is
XL
XC
XC + XL
XL – XC
The ampere-hour capacity of battery depends on
The thickness of the plates
the strength pf the electrolytes
The area of the plates
the distance between the plates
The condition in Ohm’s Law is that
ratio V/I should be constant
current should be proportional to voltage
the temperature should remain constant
the temperature should vary
If an electrical network having one or more than one voltage source, is transformed into equivalent electrical network with a single voltage source (which is short circuit current of previous circuit) with parallel internal resistance of the network with all current source replaced by their internal resistance. The above illustration is called
Thevenin’s theorem
Reciprocity Theorem
nortons theorem
Superposition theorem
For a three phase unbalanced load
The power factor of each phase will be proportional to the load
The power factor each phase will be the same
The power factor of at least one of the phases must be leading
The power factor of each phase may be different
Cellular phones operate in the frequency range of
EHF
VHF
UHF
SHF
What is the maximum allowable voltage drop for lighting circuit?
3%
5%
2%
10%
What is the maximum allowable voltage drop for feeder?
1%
2%
3%
5%
color is reserved for grounding equipment wire only
white
green
yellow
grey
The syncroscope is an instrument used to indicate the
Speed of motor
Phase relationship between the current and voltage
Phase relationship between two voltages
Phase relationship between the true power and the reactive power
The current flowing in the armature conductors of a dc motor is
ac
dc
ac as well as dc
transients
The armature current drawn by any dc motor is proportional to
The voltage applied to the motor
the torque required
The flux required in the motor
The speed of the motor
Fault level means
Voltage at the point fault
Fault current
Fault power factor
Fault MVA
If the input of the prime mover of an alternator is kept constant but excitation is increased, then
KVA will be leading
KVA will be lagging
KW will be changed
The p.f. of the load remains constant
In electroplating, the positive electrode is called the
cathode
anode
terminal
iontrap
Barrier potential of silicon diode is
. 0.1 v
0.3 v
0.4 v
0.7 v
Which of the following is an active element of a circuit?
Ideal current source
Resistance
Inductance
Capacitive
Which wave form will have the minimum rms value if they have the same peak value of voltage?
Square wave
Sine wave
Triangular Wave
Full wave rectified sine wave
The minimum armature current of a synchronous motor corresponds to operation at
0.8 p.f. lagging
unity p.f.
0 p.f. leading
0 p.f. lagging
Lap winding is best siuited for voltage, current dc generators
High, Low
Low, High
High, High
Low, Low
What is the relative permittivity of vacuum?
Unity
8.854 x 10-12
8.854
zero
On triling the number of turns of a coil the inductance
Becomes 9 times as large
3 times
1/3
Will remain the same
An external resistance is added in series with the field of a dc shunt motor. When the motor runs, the effect of resistance is
To reduce the speed of the motor
To increase the speed of the motor
To reduce the armature current drawn by the motor
To reduce the losses
Which of the following is not the method of arc dispersion?
Oil immersion contacts
Magnetic blow out of arc
Use of rectifiers
Deionization of arc path
During load shedding
System voltage is reduced
Some loads are switch off
System power factor is changed
System frequency is reduced
The capacitor in a series RC circuit at steady state is:
Open circuit
Short circuit
Transient circuit
Coupled circuit
There is no zero sequence component of the fault current for
Line to line fault
Single line to ground fault
Symmetrical fault
Double line to ground fault
The ratio of lumens reaching the work plane divided by the total lumens generated by the light is:
Room ratio
Coefficient of utilization
Illumination factor
Maintenance factor
When the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected, then
The motor stops
It runs at lower speed
t runs at the same speed
It runs at very high speed
Sensitivity of a voltmeter is expressed as
Volts/Ohm
Ohms/Volt
Ohm-Volt
1/Ohm-Volt
The dc armature winding in which the coil sides are placed a pole pitch apart is called winding.
Multiplex
Full-pitch
Fractional-pitch
Pole-pitch
