1 Crore+ students have signed up on EduRev. Have you? Download the App 
Resolution of an instrument is
The volt ampere equation for a long shunt compound motor is given by
The current through a series RLC circuit under resonance condition will be
Zerosequence currents can flow from a line to transformer bank if the windings are in
Resistivity of wire depends on
In a transistor largest dimension is that of –
Which one of the following describes correctly the effect of adding a zero to the system ?
For both lap and wave windings, there are as many commutator bars as the number of
A Lissajous pattern on an oscilloscope has 5 horizontal tangencies and 2 vertical tangencies.The frequency of the horizontal input is 1,000 Hz. What is the frequency of the vertical input ?
Negativesequence reactance of a transformer is
Current flow through a bipolar transistor is by means of –
Five resistances are connected as shown in fig.6.
The equivalent resistance between the point A and B will be
The smallest change in a measured variable to which an instrument will respond is
114.Which of the following bridges can be used for inductance measurement ?
1. Maxwell bridge 2. Hay's bridge
3. Wein bridge 4. Wheatstone bridge
Select the correct answer using the code given below:
What is the approximate input impedance of a CRO?
Which of the following relation is incorrect ?
power factor =
Dead time of the instrument is
A FET can be used as a variable –
The power of a threewire balanced system was measured by two wattmeter method. The reading of one of the wattmeter was found to be double that of the other. What is the pf of the system ?
The field coils of a dc generator are usually made of
Torque/weight ratio of an instrument indicates
......... is the best electronic device for fast switching.
123. The characteristic equation of a feedback control system is given by :s^{3} + 6s^{2} + 9s + 4 = 0 is What is the number of roots in the left half of the splane ?
An alternating e.m.f. is applied to a pure inductance such that inductive reactance is 10 W.If the frequency of a.c. is doubled, the reactance will become
A series RLC circuit will have unity power factor if operated at a frequency of
The errors introduced by an instrument fall in which category ?
The current drawn by a 120 V dc motor with back emf of 110 V and armature resistance of 0.4W is
If the power factor is below 0.5 in two wattmeter method of power measurement
The positivenegative and zero sequence impedances of a solidly grounded system under steadystate condition always follow the relations
The resistance temperature coefficient is defined as
Which of the following results in a symmetrical fault ?
The advantage of transistor over vaccum tube is –
Accuracy is defined as the
The resistance of the field regulator of a dc shunt motor is of the order of
Which is the pilotless protection method for feeder line ?
A,B,C and D represent the transmission parameters of a twoport network. when is the network reciprocal ?
The condition for the validity under Ohm's law is
The most common type of fault is
The dielectric loss of a capacitor can be measured by which one of the following ?
In MetzPrice percentage differential protection of a DY transformer, the CT secondaries connection in the primary and secondary winding of the transformer would be in the form of
Core loss in a dc machine occurs in
The relay used feeder protection is
In a normally biased NPN transistor the main current crossing the collectro junction is –
If the power factor is below 0.5 in two wattmeter method of power measurement
Which one of the following bridges is used for measurement of dielectric loss and power factor of a capacitor ?
The load current in shortcircuit calculation are neglected because
1. shortcircuit current are much larger than load currents
2. shortcircuit currents are greatly out of phase with load currents.
Which of these statement (s) is/are correct ?
Which bridge is used to determine frequency ?
The voltage coil of a single phase house energy meter
What should be the main characteristic(s) of the null detector in a bridge measurement ?
1. Accuracy. 2. Precision.
3. Sensitivity. 4. Resolution.
Select the correct answer using the code given below :
Reactance relay is normally used for protection against
The function of circuit breaker is
Holes are drilled on the opposite sides of the disc of an induction type energy meter to
In the potentiometer circuit shown in the given figure, the value of unknown voltage ‘E’ under balanced condition will be
The symmetrical components are used in the fault analysis because
Match List I with List II and select the correct answer using the codes given below the lists :
In a singlephase induction type energy meter, the lag adjustment is done to ensure that
Consider the following circuit: What is the value of current I in the 5W resistor in the circuit given in the figure ?
What is the nominal pH value of water that is to be maintained in a steam raising thermal power station ?
A cyclindrical rotor synchronous motor is switched on to the supply with its field windings shorted on them selves. It will
What is the characteristic of a good control system ?
The zerosequence current of a generator for lineto ground fault is j2.4 pu. Then the current through the neutral during the fault is
Laminations of core are generally made of—
An electric bulb rated 220 V is connected 220 v, 5 Hz source. Then, the bulb
The sensitivity of a Wheatstone bridge depends upon
A fault occurring at the terminals of an unloaded synchronous generator operating at its rate
voltage has resulted in the following values of currents and voltages.
I_{a0 }= j2.37 pu, I_{a1}=j3.05 pu, I_{a2}=j0.68 pu,
V_{a0} = V_{a1} = V_{a2} = 0.237 pu
Which one of the following faults has occurred ?
The torqueslip characteristics of a polyphase induction motor becomes almost linear at small values of slips, because in this range of slips,
In which zone the impedance Z is almost pure capacitance ?
The conductor carries more current on the surface in comparison to its core. This phenomenon is called the
In D.C. generator on noload, the air gap flux distribution in space is—
In a twoPort network, the condition for reciprocity in terms of 'h'  parameters is
In a transmission system, the weight of copper used is proportional to
The speed of a series motor at no load is —
The coupling between two magnetically coupled coils is said to be ideal if the coefficient of coupling is
A balanced 3phase system consists of
At which condition of the transformer the equivalent circuit will be as shown in the figure ?
In the circuit given in the figure, the limiting error in the power dissipation ‘I2 R’ in the resistor R is
In dc machines, the air gap flux distribution in space at no load is
In the ciurcuit shown in the baove figure, the voltage across the 2 ohm resistor is
For defining the standard metre, wave length of which material is considered ?
In case of an unbalanced starconnected load supplied from an unbalanced 3phase, 3wire
system, load currents will consist of
The permissible flux density in cold rolled grain oriented steel is about
If an RL circuit having impedance angle f is awiteched on when figure under sinusoidal voltage wave is passing trough and angle q, there will be no switching transition if
What is the value of the damping ratio of a second order system when the value of the resonant peak is unity ?
Which of the following types of errors come under systematic errors ?
1. Irregular spring tension.
2. Improper readings of an instrument.
3. Loading effects.
4. Error due to the presence of electric field or magnetic field.
The dual of a parallel RC circuit is a
In a control system , the use of negative feedback
In a power transformer, the breather is provided in order to
Zerosequence fault current is absent when fault is
A resistance of 105 ohms is specified using significant figures as indicated below :
1. 105 ohms 2. 105.0 ohms
3. 0.000105 MW
Among these
A series motor drawing an armature current of I_{a} is operating under saturated magnetic conditions. The torque developed in the motor is proportional to
The volume of copper required for an ac transmission line is inversely proportional to
Torque/weight ratio of an instrument indicates
What is the initial slope of Bode magnitude plot of a type2 system ?
A 3phase synchronous generator is operating at constant load while the excitation is adjusted to give unity pf current. If the excitation is now increased, the pf will
Which of the following distribution systems is preferred for good efficiency and high economy ?
What will be the type of the system, if the steady state performance of control system yields a non zerofinite value of the velocity error constant ?
2 videos1 docs55 tests

2 videos1 docs55 tests
