Legal Metrology • Paper-II
The positive sequence reactance will be equal to the negative sequence reactance, if the equipment is
A)
Transformer
B)
Transmission line
C)
Generator
D)
both (a) and (b)
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'Transmission line' (Option B).
Legal Metrology • Paper-II
In a nuclear power station using Boiling Water Reactor (BWR), water is used as
A)
a moderator but not as a coolant
B)
a constant but not as a moderator
C)
both moderator and coolant
D)
neither moderator nor coolant
In a BWR, ordinary water serves as both coolant and neutron moderator.
Legal Metrology • Paper-II
When will a slip ring induction motor run at super synchronous speed?
A)
If a voltage is injected in the rotor circuit in phase opposition to the rotor induced emf
B)
If an emf is injected in the rotor circuit in phase with the rotor induced emf
C)
If motor is coupled with active load
D)
If motor is coupled with passive load
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'If an emf is injected in the rotor circuit in phase with the rotor induced emf' (Option B).
Legal Metrology • Paper-II
For a fault at the terminals of a synchronous generator, the fault current is maximum for a
A)
3-phase fault
B)
3-phase to ground fault
C)
line-to ground fault
D)
line to-line fault
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'line to-line fault' (Option D).
Legal Metrology • Paper-II
For stability and economic reasons we operate the transmission line with power angle in the range
A)
10° to 25°
B)
30° to 45°
C)
60° to 75°
D)
65° to 80°
A high resistance is connected in series to limit the current through the voltmeter movement.
Legal Metrology • Paper-II
Whenever the conductors are dead-ended or there is a change in the direction of transmission line, the insulators used are of the
A)
Pin type
B)
Suspension type
C)
Strain type
D)
Shackle type
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'Suspension type' (Option B).
Legal Metrology • Paper-II
The initial slope of the bode plot gives an indication of
A)
type of the system
B)
nature of the system time response
C)
system stability
D)
gain margin
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'nature of the system time response' (Option B).
Legal Metrology • Paper-II
As compared to DOL starting, a cage induction motor with star-delta starting shall have
A)
more starting torque
B)
more starting time
C)
reduced starting current
D)
smoother acceleration
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'smoother acceleration' (Option D).
Legal Metrology • Paper-II
In a power station, the cost of generation of power reduces most effectively when
A)
diversity factor alone increases
B)
both diversity factor and load factor increase
C)
load factor alone increases
D)
both diversity factor and load factor becrease
Correct option: B — both diversity factor and load factor increase. This matches the standard definition/result for the stated question.
Legal Metrology • Paper-II
As compared to closed loop system, an open loop is
A)
more stable as well as more accurate
B)
less stable as well as less accurate
C)
more stable but less accurate
D)
less stable but more accurate
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'more stable but less accurate' (Option C).
Legal Metrology • Paper-II
The air-gap between the yoke and armature in a dc motor is kept small
A)
to achieve a stronger magnetic field
B)
to avoid overheating of the machine
C)
to avoid locking of the armature
D)
to avoid transverse motion
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'to avoid overheating of the machine' (Option B).
Legal Metrology • Paper-II
A minimum phase unity feedback system has a Bode plot with a constant slope of -20 db/decade for all frequencies. What is the value of maximum phase margin for the system?
A)
0°
B)
90°
C)
-90°
D)
180°
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is '180°' (Option D).
Legal Metrology • Paper-II
The counter e.m.f. of a d.c. motor
A)
often exceeds the supply voltage
B)
aids the applied voltage
C)
help in energy conversion
D)
regulates its armature voltage
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'help in energy conversion' (Option C).
Legal Metrology • Paper-II
If a combination of HRC fuse and circuit breaker is used, the CB operate for
A)
low overload currents
B)
short circuit current
C)
under all abnormal current
D)
the combination is never used in practice
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'low overload currents' (Option A).
Legal Metrology • Paper-II
The forward-path transfer function of unity feedback system is G(s) = K(s+2) / [(s^2 + 1)(s+4)(s-1)]. The range of K, for which will be only two closed loop RHP poles, is
A)
-33 < K < -12
B)
K < -33
C)
K < 2
D)
0 < K < 2
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'K < 2' (Option C).
Legal Metrology • Paper-II
In order to use the Routh’s Hurwitz criterion for determining the stability of sampled data system the characteristics equation 1+G(z)H(z) = 0, should be modified by using bilinear transform of
A)
z=r+1
B)
z=r-1
C)
z=(r+1)/(r-1)
D)
z=(r-1)/(r+1)
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'z=r-1' (Option B).
Legal Metrology • Paper-II
The intersection of asymptotes of root loci of a system with open loop transfer function G(s).H(s) = K / [s(s+1)(s+3)] is
A)
1.44
B)
1.33
C)
-1.44
D)
-1.33
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is '1.33' (Option B).
Legal Metrology • Paper-II
The bode-plot is valid for
A)
minimum phase network
B)
all phase network
C)
non-minimum phase network
D)
none of these
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'non-minimum phase network' (Option C).
Legal Metrology • Paper-II
The electrical stiffness of a synchronous generator connected to a very large system can be increased by
A)
increasing the excitation or power angle of the machine
B)
reducing the excitation of the synchronous reactance of the machine
C)
increasing the synchronous reactance of the machine
D)
operating the generator at a much lower MW level compared to the steady state limit
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'increasing the excitation or power angle of the machine' (Option A).
Legal Metrology • Paper-II
For a fault in a power system, the term critical clearing time is related to
A)
reactive power limit
B)
transient stability limit
C)
short circuit current limit
D)
steady state stability limit
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'reactive power limit' (Option A).
Legal Metrology • Paper-II
A power station consists of two areas connected via a tie line. While entering the data for load flow the tie line parameters and its connectivity data were inadvertently left out. If the load flow program is run with this incomplete data, then the load flow calculations will converge only if
A)
One slack bus is specified in the first area
B)
One slack bus is specified in the second area
C)
One slack bus is specified in either of the two areas
D)
Two slack buses, one in each area, are specified
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'One slack bus is specified in the second area' (Option B).
Legal Metrology • Paper-II
Which of the following methods is not used for the analysis of nonlinear control systems?
A)
phase plane method
B)
describing function method
C)
Liapunov’s method
D)
Piecewise linear method
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'describing function method' (Option B).
Legal Metrology • Paper-II
In a three phase induction motor, the rotor field rotates at synchronous speed with respect to
A)
stator
B)
rotor
C)
stator flux
D)
none of the above
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'stator flux' (Option C).
Legal Metrology • Paper-II
Gauss-Seidel iterative method can be used for solving a set of
A)
linear differential equations only
B)
linear algebraic equation only
C)
both linear and nonlinear equations only
D)
both linear and nonlinear differentialequations
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'both linear and nonlinear equations only' (Option C).
Legal Metrology • Paper-II
Given a badly underdamped control system, the type of cascade compensator to be used to improve its damping is
A)
phase-lead
B)
phase-lag
C)
phase-lag-lead
D)
notch filter
Based on established principles in Electrical / Electronics Engineering, the correct and most appropriate choice is 'phase-lag-lead' (Option C).
