Q .
Colour code of carbon resistors has only two bands.
A. True
B. False
C.
D.
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 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 units for apparent power are watts.
A. True
B. False
C.
D.
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 .
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 .
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 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 .
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 .
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 .
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 . 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 .
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 .
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 .
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 .
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 .
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 .
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 .
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 .
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 .
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 .
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 .
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 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 series RLC circuit p.f is lagging when f < resonance frequency.
A. True
B. False
C.
D.
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 .
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 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 .
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 .
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 .
Heat in calories = I2Rt/4.186.
A. True
B. False
C.
D.
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 .
A dielectric does not have leakage current.
A. True
B. False
C.
D.
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 .
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 .
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 .
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 .
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 .
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 .
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