Q .
A two branch parallel tuned circuit has a coil of resistance 100 Ω and inductance 0.005 H in one branch and 10 nF capacitor in the second branch. At resonance frequency is
A. 100 rad/sec
B. 10000 rad/sec
C. 1000 rad/sec
D. more than 10000 rad/sec
E. NA
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Q .
A 0.5 μF capacitor is connected across a 10 V battery. After a long time, the circuit current and voltage across capacitor will be
A. 0.5 A and 0 V
B. 0 A and 10 V
C. 20 A and 5 V
D. 0.05 A and 5 V
E. NA
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Q .
Laplace transform of a unit doublet U-2 (t) is
A. 1/s
B. s
C. 0
D. 1
E. NA
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Q .
A 1 μF capacitor is connected to 12 V battery. The energy stored in the capacitor is
A. 12 x 10-6 J
B. 24 x 10-6 J
C. 48 x 10-6 J
D. 72 x 10-6 J
E. NA
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Q .
A coil has resistance R and inductance L. At ω = ∞ the phase angle between voltage and current is
A. 0°
B. 180°
C. 45°
D. 90°
E. NA
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Q .
A constant k band pass filter has a pass band from 100 to 400 Hz. The resonant frequency of series and shunt arms is
A. 3000 Hz
B. 2500 Hz
C. 2000 Hz
D. 1500 Hz
E. NA
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Q .
If operator 'a' = 1 ∠120° then (1 + a + a2) =
A. -a
B. -a2
C. 1
D. 0
E. NA
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Q .
Figure shows a parallel resonant circuit having resonance frequency of 15 MHZ. At this frequency
A. its impedance is minimum
B. its impedance is maximum
C. its impedance is infinite
D. its impedance is zero
E. NA
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Q .
A system is at rest for t < 0. It is given by If steady state is reached at t = 0, then the value of angle A is given by
A. 0
B. 45 °
C. - 45°
D. ∞
E. NA
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Q .
The degree of the nodes 1, 2, 3, 4 is
A. 2
B. 3
C. 2 for 1, 2, 3, and 3 for 4
D. all 3
E. NA
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Q .
For a series R-L-C circuit tuned at resonant frequency which of the following statements is correct?
A. The voltage across inductance is greater than applied voltage
B. The voltage across capacitance is greater than applied voltage
C. The voltage across both inductance and capacitance is greater than applied voltage
D. The voltage across both inductance and capacitance is less than applied voltage
E. NA
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Q .
At t = 0+, the current i1 is
A. - V/2R
B. - V/4R
C. - V/R
D. zero
E. NA
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Q . Assertion (A): In a series resonant circuit current is maximum at resonance.
Reason (R): The inductive and capacitive reactances are equal.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
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Q .
A network N is dual of network N if
A. both of them have same mesh equation
B. both of them have same node equation
C. mesh equation of one are the node equations of the other
D. KCL and KVL equations are the same
E. NA
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Q .
For making a capacitor, the dielectric should have
A. high ∈r
B. low ∈r
C. ∈r = 1
D. ∈r neither too high nor too low
E. NA
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Q .
At resonance the network function magnitude will be
A. k/a
B. k/b
C. c
D. k/a + b
E. NA
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Q . Assertion (A): The number of basic loops is equal to number of links.
Reason (R): The graph theory helps in choosing independent variables in circuit analysis.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
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Q .
, i(t) =
A. 3e-4t - e-5t
B. 3e-4t - 2e-3t
C. 2e-4t - 5e-2t
D. 3e-4t - e-t
E. NA
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Q .
A network is said to be non-linear if it does not satisfy
A. homogeneity condition
B. superposition condition
C. both (a) and (b)
D. associative condition
E. NA
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Q .
The double energy transients occur in the
A. pure inductive coil
B. R-L circuit
C. R-C circuit
D. R-L-C circuit
E. NA
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Q .
The capacitance of a parallel plate capacitor varies as per the equation C(t) = C0 (1 - cos ωt). It is connected to a battery of V volts. The equation for current is
A. ωC0V (1 - cos ωt)
B. ωC0V(1 - sin ωt)
C. ωC0V (1 - sin 2ωt)
D. ωC0V sin ωt
E. NA
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Q . Assertion (A): A graph can have many trees.
Reason (R): The number of tree branches is equal to number of nodes.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
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Q .
An RLC series circuit is excited by a step voltage E. The circuit current at t = 0 is
A. E/R
B. E/LC
C. zero
D. infinity
E. NA
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Q .
In a Hurwitz polynomial
A. all coefficients are non-negative
B. the coefficients may be positive or negative
C. all coefficients are negative
D. all coefficients are non-negative and all zeros should be either in left half plane or simple on the imaginary axis
E. NA
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Q .
System function , For a signal sin 2t, the steady state response is
A. 1/8
B. ∞
C. 0
D. 8
E. NA
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Q .
The current rating of a cable depends on
A. length of cable
B. diameter of cable
C. both length and diameter of cable
D. none of the above
E. NA
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Q .
An RC series circuit is charged by a voltage E. After a long time the battery is removed and a short circuit is placed across R-C. Then
A. the polarity of voltage across R is same during discharge and during charge
B. the polarity of voltage across R during discharging is opposite to that during charging
C. the polarity of voltage across R depends on time constant RC
D. none of the above
E. NA
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Q .
For an ideal transformer
A. only Y parameter exist
B. only Z parameter
C. Z, Y both exist
D. neither Z parameter nor Y parameter exist
E. NA
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Q .
In a pure capacitive circuit if the supply frequency is reduced to 1/2, the current will
A. be reduced by half
B. be doubled
C. be four times as high
D. be reduced to one fourth
E. NA
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Q .
In a minimum function
A. the degree of numerator and denominator are equal
B. the degree of numerator and denominator are unequal
C. the degree of numerator is one more than degree of denominator
D. the degree of numerator is one less than degree of denominator
E. NA
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Q .
For a transmission line open circuit and short circuit impedances are 20 Ω and 5 Ω. Then characteristic impedance is
A. 100 Ω
B. 50 Ω
C. 25 Ω
D. 10 Ω
E. NA
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Q .
Heat in calories = I2Rt/4.186.
A. True
B. False
C.
D.
E. NA
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Q .
In an RC series circuit R = 100 Ω and XC = 10 Ω. In this circuit
A. the current and voltage are in phase
B. the current leads the voltage by about 6°
C. the current leads the voltage by about 84°
D. the current lags the voltage by about 6°
E. NA
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Q .
Two coupled coils lie in parallel planes such that 50% of magnetic flux produced by one links the other. The coefficient of coupling is
A. 0.5
B. 0.25
C. 0.125
D. 0.5
E. NA
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Q .
A black box has one of the elements our of R, L, C. when a 220 V a supply is connected the current supplied by source is I. when a 0.1 F capacitor is connected in parallel with the box, the current is 2I. The element is
A. resistance
B. inductance
C. 0.1 F capacitance
D. not identifiable on the basis of given data
E. NA
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Q .
The circuit shown in figure is a
A. low pass filter
B. high pass filter
C. band pass filter
D. band stop filter
E. NA
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Q .
In figure, the switch has been in closed position for a long time. At t = 0, the switch is opened. At t = 0+, the current R1 is
A. 8 A
B. 4 A
C. 6 A
D. 2 A
E. NA
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Q .
What are the ABCD parameters of the single elements circuit given below?
A.
B.
C.
D.
E. NA
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Q . Assertion (A): A band elimination filter attenuates signals whose frequencies lie between the cutoff frequencies.
Reason (R): A band elimination circuit is very different from band pass circuit.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
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Q .
Pick the correct statement
A. Delta connection draws same current as star connection
B. Delta connection draws 3 times as much current as star connection
C. Delta connection draws of the current of star connection
D. Delta connection draws of the current of delta connection
E. NA
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Q .
Two similar coupled coils are connected in series. The total inductance in series aiding connection is 100 mH. If currents is 3 A, the energy stored in magnetic field is
A. 0.9 J
B. 0.45 J
C. 0.225 J
D. 1.8 J
E. NA
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Q .
Which one of the following is a cut set of the graph in the given figure?
A. 1, 2, 3, and 4
B. 2, 3, 4, and 6
C. 1, 4, 5, and 6
D. 1, 3, 4, and 5
E. NA
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Q .
The voltage of single phase supply to residential consumers in India is
A. 400 V
B. 230 V
C. 2.2 kV
D. 11 kV
E. NA
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Q .
The units for apparent power are watts.
A. True
B. False
C.
D.
E. NA
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Q .
The terms RMS and average values apply only to sine waves.
A. True
B. False
C.
D.
E. NA
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Q .
A cable has an insulation resistance of 1010 ohms. If the length is doubled, the insulation resistance will be
A. 2 x 1010 Ω
B. 0.5 x 1010 Ω
C. 1010 Ω
D. 4 x 1010 Ω
E. NA
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Q .
In figure the phase plot
A. will be 90° at ω = 0 and 0° at ω = ∞
B. will be 0° at ω = 0 and 90° at ω = ∞
C. will be 45° at ω = 0 and 0° at ω = ∞
D. will be 45° at ω = 0 and 90° at ω = ∞
E. NA
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Q .
A dielectric should have poor heat conductivity.
A. True
B. False
C.
D.
E. NA
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Q .
A two branch tuned circuit has a coil of resistance R and inductance L in one branch and capacitance C in the second branch. If R is increased, the dynamic resistance
A. increases
B. decreases
C. remains constant
D. may increases or decreases
E. NA
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Q .
In a two terminals network the O.C. voltage measured at the given terminals is 100 V and s.c., currents at the same terminals 5 A. If a load of 80 Ω resistance is connected at the terminals, load current is
A. 1 A
B. 1.25 A
C. 6 A
D. 6.25 A
E. NA
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Q .
For the network of figure, z11 =
A. 5/3 Ω
B. 3/2 Ω
C. 2 Ω
D. 2/3 Ω
E. NA
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Q .
Which one of the following is a passive device/Component?
A. Transformer
B. Oscillator
C. Generator
D. None
E. NA
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Q .
The resistance of the aluminium conductor (r = 2.83 x 10-8 Ωm) in figure is
A. 0.001 Ω
B. less than 0.001 Ω
C. more than 0.001 Ω
D. more than 0.002 Ω
E. NA
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Q .
The condition on R, L and C such that the step response y(t) in the figure has no oscillation, is
A.
B.
C.
D.
E. NA
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Q .
The relation AD - BC = 1 where A, B, C, D are transmission parameters of a network is valid for
A. every network
B. passive but not reciprocal network
C. passive and reciprocal network
D. both active and passive networks
E. NA
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Q .
The dual of a node is
A. mesh
B. principal node
C. tree branch
D. link
E. NA
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Q .
Norton's theorem reduces a two terminal network to
A. a constant current source and an impedance is parallel
B. a constant current source and an impedance in series
C. a constant voltage source and an impedance in parallel
D. a constant voltage source and an impedance in series
E. NA
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Q .
A reactance function
A. has a pole at origin
B. has a zero at origin
C. may have a pole or zero at origin
D. has a pole or zero at origin and a pole or zero at infinity
E. NA
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Q .
In an R-C circuit, there is an initial voltage of 3 V across the capacitor. In s domain equivalent circuit, the voltage source to take into account the initial voltage has a strength of
A.
B. 3s
C.
D. 3Cs
E. NA
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Q .
For a two- port reciprocal network, the output open circuit voltage divided by the input current is equal to
A. B
B. Z12
C. 1/y12
D. h12
E. NA
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Q .
If a resistance R of 1 Ω is connected between A and B in figure, current flowing through R is
A. 1 A
B. 0.5 A
C. 0.25 A
D. 0.125 A
E. NA
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Q .
Consider the following statements associated with two port networks. Z12 = Z21Y12 = Y21h12 = h21AD - BC = 1 Which one of the statement given above are correct?
A. 1, 2, 3
B. 2, 3, 4
C. 1, 3, 4
D. 1, 2, 4
E. NA
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Q .
A circuit is replaced by its Thevenin's equivalent to find current through a certain branch. If VTH = 10 V and RTH = 20 Ω, the current through the branch
A. will always be 0.5 A
B. will always be less than 0.5 A
C. will always be equal to or less than 0.5 A
D. may be 0.5 A or more or less
E. NA
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Q .
The graph of a network is shown in the figure. Which one of the figure shown is not a tree of the graph?
A.
B.
C.
D.
E. NA
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Q .
The average value of the waveform is
A. 2 V
B. 0 V
C. 4 V
D. 3 V
E. NA
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Q .
In a network
A. the number of tree branches is always less than the number of links
B. the number of tree branches is always more than the number of links
C. the number of tree branches and links are always equal
D. the number of tree branches has no relation with the number of links
E. NA
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Q .
Reciprocity theorem is applicable to
A. circuits with one source
B. circuits with only one independent source
C. circuits with any number of sources
D. circuits with any number of independent sources
E. NA
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Q .
Evaluate the value of 2 [u (t - 1) - u (1 - 2t)] (u ( t + 1) + u (t)) at t = 3 sec.
A. 0
B. 4
C. ∞
D. 1
E. NA
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Q .
The phase difference between them is __________ degrees.
A. 15
B. 50
C. 60
D. 105
E. NA
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Q .
The poles with greater displacement from the real axis correspond to
A. higher frequencies of oscillation
B. stable response
C. lower frequencies of oscillation
D. unbounded output
E. NA
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Q .
The following table gives some Laplace transforms and the functionsf(t) F(s)1.δ(t) s2. u(t) 1/s3. tu(t) 2/s24. t2u(t) 2s3Of these the correctly matched pairs are
A. 2 and 4
B. 1 and 4
C. 2 and 4
D. 1 and 2
E. NA
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Q .
An RLC series circuit has . If the poles p1 and p1* are close to jω axis, then
A. Q is high
B. Q is low
C. ω0 is high
D. bandwidth is large
E. NA
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Q .
Colour code of carbon resistors has only two bands.
A. True
B. False
C.
D.
E. NA
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Q .
The unit of permeability is
A. T
B. Wb
C. H/M
D. H
E. NA
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Q .
Poles and zeros of a driving point function of a network are simple and alternate on jω axis. The network consists of
A. R and C
B. L and C
C. R and L
D. R, L and C
E. NA
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Q .
At a frequency less than the resonant frequency
A. series circuit is inductive and parallel circuit is capacitive
B. series circuit is capacitive and parallel circuit is inductive
C. both circuits are capacitive
D. both circuits are inductive
E. NA
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Q .
The current I flowing in the branch is
A. -12 A
B. 12 A
C. 3 A
D. -3 A
E. NA
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Q .
In an R-L-C circuit, v(t) = 20 sin (314 t + 5 p /6) and i(t) = 10 sin (314 t + 2p /3). The p.f of the circuit is
A. 0.5 lead
B. 0.866 lag
C. 0.866 lead
D. 0.5 lead
E. NA
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Q . Assertion (A): When a square periodic wave is applied to an RC circuit, the voltage across capacitor is observed to be a triangular periodic wave.
Reason (R): The RC circuit works as integrator and its time constant is much larger than time period of input wave.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
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Q .
For representing two sinusoidal voltages on a phasor diagram
A. Both voltages must be of the same frequency
B. Both voltages must be sinusoidal but may be of different frequencies
C. One of the voltages must be of 50 Hz
D. The frequency of one must be integral of that of other
E. NA
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Q .
For an RC admittance function
A. the lowest critical frequency is a zero
B. the highest critical frequency is a pole
C. the lowest critical frequency is zero and the highest critical frequency is a pole
D. the lowest critical frequency is a pole
E. NA
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Q .
The inverse Fourier transform of is
A. sin ωt
B. cos ωt
C. sgn (t)
D. u (t)
E. NA
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Q .
Kirchoff's laws are applicable to
A. steady state conditions only
B. transient conditions only
C. both steady state and transient condition
D. both steady state and transient condition but with some constraints
E. NA
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Q .
In an R-C series circuit excited by a voltage E, the charge across capacitor at t = 0+ is
A. 0
B. CE
C. CE (1 - e-t/RC)
D. none of the above
E. NA
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Q .
Kirchoff's laws are applicable to
A. dc only
B. ac sinusoidal wave only
C. dc and ac sinusoidal waves
D. all wave shapes
E. NA
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Q .
As compared to the number of network elements in Brune synthesis, the number of network elements Bott-and Duffin in realization is
A. more
B. less
C. equal
D. any of the above
E. NA
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Q .
An electrical network with 8 independent nodes will have __________ nodal equations.
A. 4
B. 6
C. 7
D. 8
E. NA
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Q .
Wave A = 100 sin ωt and wave B = 100 cos ωt. Then
A. rms values of the two waves are equal
B. rms values of A is more than that of B
C. rms values of A is less than that of B
D. rms values of the two waves may or may not be equal
E. NA
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Q .
A 3 phase balanced supply feeds 3 phase unbalanced load. Power supplied to the load can be measured by using 2 wattmeterone wattmeter3 wattmeter Which of the above statements is correct?
A. 1 and 2
B. 1 and 3
C. 2 and 3
D. 3 alone
E. NA
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Q .
In an unloaded transformer, the fluxes limiting the primary and secondary are 30 mWb and 20 mWb. The coefficient of coupling is
A. 1
B. 0.1
C. 0.33
D. 0.67
E. NA
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Q .
In the transformer shown in the figure, the inductance measured across the terminal 1 and 2 was 4 H with open terminals 3 and 4. It was 3H when the terminals 3 and 4 were short circuited. The coefficient of coupling would be
A. 1
B. 0.707
C. 0.5
D. indetermine due to insufficient data
E. NA
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Q .
For the circuit in figure, fed by a unit step voltage, vc =
A. 1 - e-t/RC
B. e-t/RC
C. et/RC
D. 1
E. NA
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Q .
Choose the correct option Transit period is the time between two steady stateTransient Response is the response due to internal energy stored in circuitTransit response is also called natural responseTransit response arises due to presence of C and L in the circuitTransit is due to R, L, C in the circuit
A. 4, 3, 2 , 1
B. 5, 4, 3, 2
C. 5, 4, 3, 1
D. 5, 1, 4
E. NA
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Q .
In liquids charge carriers are electrons only.
A. True
B. False
C.
D.
E. NA
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Q .
In series as well as parallel resonant circuits, increasing the value of resistance would lead to
A. decrease in bandwidth of both the circuits
B. increase in bandwidth of both the circuits
C. decrease in bandwidth in series circuit and increase in parallel circuit
D. increase in bandwidth in series circuit and decrease in parallel circuit
E. NA
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Q .
The Laplace transform of a function f(t) u(t) is __________ where f(t) is periodic with period T, and y(S) times the L.T. of f(t) for first period. Then
A. s
B.
C. eTs
D.
E. NA
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Q .
and i(t) is a unit step, then V(t) in the steady state is given by
A. 4/9
B. 4/3
C. 0
D. ∞
E. NA
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Q .
In an ac circuit that delivers constant power at varying p.f., the current is
A. lowest when p.f. is leading
B. lowest when p.f. is lagging
C. lowest when p.f is unity
D. the same for all power factors
E. NA
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Q .
A series RL circuit has . If a voltage 4 sint + 4t is applied, the steady state current will be
A. 4 sin (4t - 45°)
B.
C.
D.
E. NA
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Q .
If current is less than 20 mA and time of contact is very small, the effect of current on human body is likely to be temporary.
A. True
B. False
C.
D.
E. NA
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Q .
C = (2) (energy)/V2
A. True
B. False
C.
D.
E. NA
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Q .
A constant k low pass filter has fc = 1000 Hz. At f = 500 Hz, the phase shift is
A. p
B. zero
C. more than p
D. less than p
E. NA
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Q .
The ability of a radio receiver to discriminate between different input signals and to accept only one definite signal is called its
A. sensitivity
B. attenuation
C. selectivity
D. modulation
E. NA
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Q .
Current in a 2H inductance in 10e-t A. Admittance of the inductor is
A. -0.5 mho
B. 0.5 mho
C. 5 mho
D. 10 mho
E. NA
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Q .
In the analogy between electric and magnetic circuits permeability is analogous to
A. resistivity
B. conductivity
C. electric field intensity
D. current density
E. NA
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Q .
In figure, the ratio V(s)/I(s) is
A. R
B. R + sL
C.
D.
E. NA
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Q .
While using Maxwell bridge, the Q factor of a coil is obtained as
A. 1/ωCR
B. ωCR
C. ωC/R
D. R/ωC
E. NA
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Q .
The colour on the extreme left in general purpose fixed resistors represents
A. first significant digit
B. tolerance
C. wattage rating
D. voltage rating
E. NA
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Q .
If Ia, Ib, Ic are line currents and Ia0 is the zero sequences component of Ia then
A. Ia0 = Ia
B. Ia0 = Ia + Ib + Ic
C.
D.
E. NA
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Q .
The drift velocity of electrons is
A. very small as compared to speed of light
B. equal to speed of light
C. almost equal to speed of light
D. half the speed of light
E. NA
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Q .
An RLC series circuit has Q = 100 and ω0 = 20 rad/sec. The bandwidth is
A. 0.2 rad/sec
B. 2 rad/sec
C. 20 rad/sec
D. 2000 rad/sec
E. NA
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Q .
Figure shows a dc circuit fed by a current source. With respect to terminals AB, Thevenin's voltage and Thevenin's resistance are
A. VTH = 5 V, RTH = 0.75 Ω
B. VTH = 2.5 V, RTH = 0.75 Ω
C. VTH = 2.5 V, RTH = 1 Ω
D. VTH = 5 V, RTH = 1 Ω
E. NA
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Q .
A network contains linear resistors and ideal voltage sources. If values of all the resistors are doubled, then the voltage across each resistor is
A. half
B. doubled
C. increase by 4 times
D. no change
E. NA
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Q .
The polynomial P (s) = (s - 1) (s2 + 1) (s + 2) (s + 3) is
A. Hurwitz but not strictly Hurwitz
B. not Hurwitz
C. strictly Hurwitz
D. anti/Hurwitz
E. NA
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Q .
A sinusoidal current having peak value of 7.07 A is superimposed on dc of 5A. If a hot-wire ammeter is used to measure the combined current in the circuit, it will indicate __________ ampere.
A. 7.07
B. 10
C. 12.07
D. 2.07
E. NA
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Q .
The colour code of a carbon resistance is yellow-violet-orange silver. The value of resistance is
A. 57000 Ω ± 5%
B. 47000 Ω ± 10%
C. 47000 Ω ± 5%
D. 57000 Ω ± 5%
E. NA
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Q .
RMS value of i(t) = 10[1 + sin (- t)] is
A. 10
B. 10/2
C. l50
D. 102
E. NA
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Q .
Consider the following: Energy storage capability of basic passive elements is due to the fact thatresistance dissipates energycapacitance stores energyinductance dissipates energy Which of the above is/are correct?
A. 1, 2, and 3
B. 1 and 3
C. 3 only
D. 1 and 2
E. NA
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Q . Assertion (A): is positive real.
Reason (R): For a positive real function Re[H(jω)] ≥ 0 for 0 ≤ ω ≤ ∞.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
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Q .
The dual of a link is
A. twig
B. node
C. loop
D. tree branch
E. NA
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Q .
A network is said to be two port network if there is no independent source in the networkno dependent source in the networknon-linear component in the circuitno external connection exist between I/P and 0/P
A. 1, 2, 3
B. 3, 4, 2
C. 1, 3, 4
D. 4, 3, 1, 2
E. NA
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Q .
A capacitor used for power factor correction is single phase circuit decreases
A. power factor
B. line current
C. both line current and p.f.
D. the line current and increases p.f.
E. NA
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Q .
Two coils having equal resistance but different inductances are connected in series. The time constant of the series combination is
A. average of the time constants of individual coils
B. sum of the time constants of the individual coils
C. geometric mean of the time constants of individual coils
D. product of the time constants of the individual coils
E. NA
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Q .
When a current flows through a conductor,
A. an electric field exists at all points within the conductor
B. electric field exists only at all points on the surface of the conductor
C. electric field exists only at ends of the conductor
D. any of the above depending on magnitude of current
E. NA
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Q .
The impedance of an RC series circuit is 12 Ω at f= 50 Hz. At f= 200 Hz, the impedance will be
A. more than 12
B. less than 3
C. more than 3 Ω but less than 12 Ω
D. more than 12 Ω but less than 24 Ω
E. NA
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Q .
Giga watt is equal to
A. 1012 W
B. 109 W
C. 106 W
D. 103 W
E. NA
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Q .
In solid dielectrics the rate of deterioration doubles for every 10-12°C rise in temperature.
A. True
B. False
C.
D.
E. NA
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Q .
In the transformer shown in figure, the inductance measured across terminal 1 and 2 was 4 H with terminals 3 and 4 open. It was 3H when terminals 3 and 4 are short circuited. The coefficient of coupling is
A. 1
B. 0.707
C. 0.5
D. indeterminate due to insufficient data
E. NA
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Q .
The parameter A of a two port network is equal to
A. V2/V1 with I1 = 0
B. V1/I2 with V2 = 0
C. I1/I2 with V2 = 0
D. V1/V2 with I2 = 0
E. NA
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Q .
Which of the following is correct for a driving point functions?
A. The real parts of all poles must be negative
B. The real parts of all poles and zeros must be negative
C. The real parts of all poles and zeros must be negative or zero
D. The real parts of all zeros must be negative
E. NA
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Q .
A coil is connected across a 200 V, 50 Hz supply and takes a current of 10 A. The loss in the coil is 1000 W. The impedance and resistance of the coil are
A. 10 Ω, 8 Ω
B. 15 Ω, 8 Ω
C. 20 Ω, 10 Ω
D. 30 Ω, 15 Ω
E. NA
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Q .
In a series RLC circuit the phase angle θ of impedance Z ∠θ is positive. The circuit will behave as
A. resistive circuit
B. RC circuit
C. RL circuit
D. either RL or RC circuit
E. NA
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Q .
An ac network has two sources of the same frequency. The currents in one branch when the sources act independently are 10 ∠30° A and 10 ∠60° A. When both sources act, the current in the branch should be
A. 19.32 ∠45°
B. 15 ∠45°
C. 20 ∠45°
D. zero
E. NA
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Q . Assertion (A): In drawing an electric circuit analogous to a mechanical circuit, spring is replaced by capacitance.
Reason (R): The behaviour of a spring and capacitor are similar.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
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Q .
An air cored coil has an inductance of 0.3 H. If another coil has an iron core of μr = 500, the remaining quantities being the same, the inductance of the second coil will be
A. 0.3 H
B. 0.3 x 500 H
C.
D. none of the above
E. NA
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Q .
In a series RLC circuit p.f is lagging when f < resonance frequency.
A. True
B. False
C.
D.
E. NA
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Q .
Henry is equivalent to
A. Volts/Ampere
B. Weber/Volt
C. Weber/Ampere
D. Weber/Ampere2
E. NA
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Q .
An ideal current source has
A. infinite source resistance
B. zero source resistance
C. large value of source resistance
D. finite value of source resistance
E. NA
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Q .
Which of the following pairs are correctly matched? Brune's realisation : realisation with ideal transformer.Cauer realisation : ladder realisation.Bott Duffin realisation : with non ideal transformer. Select the answer using the following codes:
A. 1, 2 and 3
B. 2 and 3
C. 1 and 3
D. 1 and 2
E. NA
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Q .
A dielectric does not have leakage current.
A. True
B. False
C.
D.
E. NA
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Q .
If H(s) is positive real, 1/H(s)
A. is positive real
B. is not positive real
C. may or may not be positive real
D. must possess some other properties also if it is to be positive real
E. NA
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Q .
For a series circuit of R and variable XL the admittance locus is
A. a semicircle in first quadrant
B. a semicircle in fourth quadrant
C. a straight line in first quadrant
D. a straight line in fourth quadrant
E. NA
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Q .
If resistance is 20 Ω and inductance is 2 H in a R-L series circuit, then time constant of this will be
A. 0.001 s
B. 0.1 s
C. 10 s
D. 100 s
E. NA
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Q .
A variable resistance R and capacitive reactance XC are connected in series. As R is varied, the locus of Z is
A. a straight line parallel to Y axis in 4th quadrant
B. a straight line parallel to X axis in 4th quadrant
C. a straight line parallel to Y axis in second quadrant
D. a straight line parallel to Y axis in first quadrant
E. NA
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Q .
A series RLC circuit is supplied from a variable frequency source. The resonant frequency is ω0. The voltage across L is maximum at a frequency
A. equal to ω0
B. slightly less than ω0
C. slightly more than ω0
D. none of the above
E. NA
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Q . Assertion (A): In an R-L circuit having high inductance, the rise of current is very slow.
Reason (R): The time constant of R-L circuit is L/R.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
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Q .
The first and the last critical frequencies (singularities) of a driving point impedance function of a passive network having two kind of elements, are a pole and a zero respectively. The above property will be satisfied by
A. RL network only
B. RC network only
C. LC network only
D. RC as well as RL network
E. NA
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Q .
In figure
A. Wave A is lagging wave B by ∠θ
B. Wave A is leading wave B by ∠θ
C. Wave A is lagging wave B by ∠θ and the two waves have same rms values
D. Wave A is lagging wave B by ∠θ and the two waves have different rms values
E. NA
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Q .
The distance between the plates of a parallel plate capacitor is d. The dielectric is in two parts, each of equal thickness but dielectric constants ∈1 and ∈2 respectively. The total capacitance will be proportional to
A.
B. ∈1 - ∈2
C.
D. ∈1∈2
E. NA
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Q .
The first critical frequency nearest the origin of the complex frequency plane for an RL driving point impedance will be
A. a zero in left half plane
B. a zero in right half plane
C. a pole in left half plane
D. a pole or zero in left half plane
E. NA
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Q .
The impedance matrices of two, two-port network are given by and . If these two networks are connected in series, the impedance matrix of the resulting two-port network will be
A.
B.
C.
D. indeterminate
E. NA
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Q .
For an RC admittance function
A. all poles and zeros are simple
B. all poles and zeros are simple and lie on negative real axis
C. all poles and zeros lie on imaginary axis
D. all poles and zeros lie on positive real axis
E. NA
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Q .
Electric shock is
A. always fatal
B. never fatal
C. sometimes fatal
D. always disfiguring
E. NA
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Q .
For a reactance function H(s)
A. Re [H(jω)] is positive for ω ≥ 0
B. Re [H(jω)] is zero for ω ≥ 0
C. Re [H(jω)] is positive or zero for ω ≥ 0
D. Re [H(jω)] is zero or negative for ω ≥ 0
E. NA
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Q .
A capacitor is needed for an ac circuit of 230 V, 50 Hz the peak voltage rating of the capacitor should be
A. 230 V
B. 0.5 x 230 V
C. 2 x 230V
D. 230/2 V
E. NA
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Q .
In a circuit with capacitance connected to ac source, the rate of change of capacitor voltage is constant.
A. True
B. False
C.
D.
E. NA
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Q .
The time constant of the network shown in figure is, when switch is closed.
A. 2RC
B.
C. RC/2
D. none
E. NA
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Q .
A series RLC circuit has a resonant frequency of 1000 Hz. The maximum voltage across C is likely to occur at a frequency of about
A. 1000 Hz
B. 2000 Hz
C. 1025 Hz
D. 975 Hz
E. NA
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Q .
A sinusoidal voltage has peak to peak value of 100 V. The rms value is
A. 50 V
B. 70.7 V
C. 35.35 V
D. 141.41 V
E. NA
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Q .
The series element in band pass filter is
A. capacitive
B. inductive
C. parallel combination of inductance and capacitance
D. series combination of inductance and capacitance
E. NA
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Q .
Two networks are cascaded through an ideal buffer. If td1 and td2 are delay times of network, the overall delay time is
A. td1 + td2
B. t2d1 + t2d2
C. td1 + td2
D.
E. NA
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Q .
In the circuit shown in the given figure, switch k is closed at t = 0. The circuit was initially relaxed then which one of the following sources of v(t) will produce maximum current at t = 0+?
A. Unit step
B. Unit impulse
C. Unit ramp
D. Unit step plus unit ramp
E. NA
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Q .
In a parallel resonant circuit, the circuit current at resonance is maximum.
A. True
B. False
C.
D.
E. NA
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Q . Assertion (A): If Z1(s) and Z2(s) are positive real then Z1(s) + Z2(s) as well as 1/Z1(s) and 1/Z2(s) are positive real.
Reason (R): The poles of a positive real function are real or occur in conjugate pairs.
A. Both A and R are true and R is correct explanation of A
B. Both A and R are true and R is not the correct explanation of A
C. A is true but R is false
D. A is false but R is true
E. NA
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Q .
For an m-derived high pass filter
A. True
B. False
C.
D.
E. NA
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Q .
An RLC series circuit is underdamped. To make it overdamped, the value of R
A. has to be increased
B. has to be decreased
C. has to be increased to infinity
D. has to be reduced to zero
E. NA
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Q .
In an ac circuit, the maximum and minimum values of power factor can be
A. 2 and 0
B. 1 and 0
C. 0 and -1
D. 1 and -1
E. NA
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Q .
Power factor of the following circuit will be unity
A. inductance
B. capacitance
C. resistance
D. both (a) and (b)
E. NA
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Q .
Open-circuit voltage is the potential difference between two point when the impedance between these points is
A. zero
B. infinity
C. capacitive
D. reactive
E. NA
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Q .
A network has two branches in parallel. One branch contains impedance Z1 and the other branch has impedance Z2. If it is fed from an ac voltage V of frequency f, the current through Z1 depends, on
A. V, Z1, Z2
B. V, Z1
C. Z1, Z2
D. V, Z1, f
E. NA
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Q .
If A = 3 + j1, A4 =
A. 3.16 ∠18.4°
B. 100 ∠73.72°
C. 100 ∠18.4°
D. 3.16 ∠73.22°
E. NA
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Q .
Two port circuits are connected in parallel. To determine the response, it is more convenient to use
A. O.C. impedance parameters
B. S.C. admittance parameters
C. ABCD parameters
D. h parameters
E. NA
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Q .
A two branch parallel circuit has a 20 Ω resistance and 1 H inductance in one branch and a 100 μF capacitor in the second branch. It is fed from 100 V ac supply, at resonance, the input impedance of the circuit is
A. 500 Ω
B. 50 Ω
C. 20 Ω
D. 5 Ω
E. NA
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Q .
Two coils having self inductances of 10 mH and 40 mH are mutually coupled. The maximum possible mutual inductance is
A. 40 mH
B. 20 mH
C. 10 mH
D. 5 mH
E. NA
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Q .
The Kirchoff's laws fail in which of the following circuits?
A. Linear circuits
B. Non-linear circuits
C. Lumped parameters circuits
D. Distributed parameters circuits
E. NA
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Q .
A series RC circuit has R = 5 Ω and C = 10 μF. The current in the circuit is 5 sin 20000t. The applied voltage is
A. 252 sin (20000t + 45°)
B. 252 sin (20000t - 45°)
C. 252 sin 20000t
D. 252 sin (20000t - 90°)
E. NA
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Q .
A series RL circuit is excited by a voltage v(t) = Ve-at such that a = R/L. Then the circuit current is
A.
B.
C.
D.
E. NA
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Q .
Thevenin's impedance of an ac network is in general
A. resistance
B. R and L in series
C. R and C in series
D. Either R and L or R and C in series
E. NA
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Q .
A current is flowing through a conductor with non-uniform area of cross-section. Then
A. current will be different at different cross-sections.
B. current will be the same at all the cross-sections.
C. current will be different but current density will be same at all the cross-sections
D. current will be the same but current density will be different at different cross-sections.
E. NA
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Q .
The resistance of a 230 V, 100 W lamp is
A. 529 Ω
B. 2300 Ω
C. 5290 Ω
D. 23 Ω
E. NA
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Q .
A capacitor stores 0.15C at 5 V. Its capacitance is
A. 0.75 F
B. 0.75 μF
C. 0.03 F
D. 0.03 μF
E. NA
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Q .
The flux linkage ψ, self inductance L and current i are related as
A. ψ = L/i
B. ψ = Li
C. ψ = Li2
D.
E. NA
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Q .
In the given circuit, viewed from AB, the circuit can be reduced to an equivalent circuit as
A. 5 volts source in series with 10 Ω resistor
B. 7 volts source in series with 2.4 Ω resistor
C. 15 volts source in series with 2.4 Ω resistor
D. 1 volt source in series with 10 Ω resistor
E. NA
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Q .
The electrical energy required to heat a bucket of water to a certain temperature is 2 kWh. If heat losses, are 25%, the energy input is
A. 2.67 kWh
B. 3 kWh
C. 2.5 kWh
D. 3.5 kWh
E. NA
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Q .
If operator 'a' = 1 ∠120° then (1 - a) =
A. 3
B. 3 ∠ - 30°
C. 3 ∠ + 30°
D. 3 ∠60°
E. NA
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Q .
Kirchoff's laws are applicable to
A. dc circuits
B. circuits with sinusoidal excitation only
C. dc circuits and circuits with sinusoidal excitation
D. circuits with any excitation
E. NA
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Q .
A capacitor is considered to be completely charged in __________ time constant.
A. one
B. three
C. five
D. eight
E. NA
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Q .
A 3 phase star-connected load has one capacitor C in R phase and two equal resistances in Y and B phases.The phase sequence is RBY. Then
A. VB0 > VY0
B. VB0 < VY0
C. VB0 = VY0
D. VB0 = VBY
E. NA
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Q .
The poles and zeros of a positive real functions are real or occur in conjugate pair.