InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 451. |
In the circuit shown in figure, for different values of R, the values of V and I are given. Other elements remaining the same. when R = ∞, V = 5 volt |
| Answer» When R = ∞, V = 5v, Voc = 5V circuit is open When R = 0, I = 2.5A Isc = 2.5 circuit short circuited Hence the voltage across 3 Ω is 3 volt. | |
| 452. |
Which statement is true for an ac circuit? |
| Answer» Active and apparent power are equal for resistive circuit. Otherwise active power is less than apparent power. | |
| 453. |
Three inductors each 30 mH are connected in delta. The value of inductance or each arm of equivalent star is |
| Answer» | |
| 454. |
If the iron core of a coil is removed so that it becomes an air cored coil, its inductance |
| Answer» μr for air is 1 while μr for iron is more than 1. | |
| 455. |
Given I = 20 A, V = 20 V, the current I in the 3 Ω resistance is given by |
| Answer» Is = 20, vs = 20 Using superposition theorem with vs = 0 Is = 0, current in 3Ω in opposite direction, net current 8A - 4A 4A. | |
| 456. |
A periodic voltage () = 1 + 4 sin ω + 2 cos ω is applied across a 1 ohm resistance. The power dissipated is |
| Answer» | |
| 457. |
A constant high pass section has a characteristic impedance of 300 Ω at = ∞ . At = , the characteristic impedance will be |
| Answer» For constant k high pass p section At f = fc, Z0p = infinite. | |
| 458. |
If A = 4∠7°, A is |
| Answer» | |
| 459. |
A square current wave of magnitude 1 A is applied to an element for 5 seconds. The voltage across the element rises linearly from 0 to final value linearly. The element is |
| Answer» Charge across capacitance increases linearly. Since capacitance is constant, voltage increases linearly. | |
| 460. |
In figure, E = 1 V (rms value). The average power is 250 mW. Then phase angle between E and I is |
| Answer» EI cos θ = 0.25 or I cos θ = 0.25 From above equations cos θ = 0.707 and θ = 45°. | |
| 461. |
A thermistor is used for |
| Answer» The resistance of a thermistor decreases with increases in temperature. It is used to monitor hot spot temperature of electric machines. | |
| 462. |
For the three coupled coils shown in figure, KVL equation is |
| Answer» M12 is positive while M23 and M13 are negative because of dots shown in figure. | |
| 463. |
Figure shows a dc circuit. The Thevenin's equivalent circuit at terminals - is |
| Answer» A current source with series resistance is not feasible. | |
| 464. |
The dependent current source shown in given figure. |
| Answer» P = I2.R 16 x 5 80 W, Voltage source and current source both are in opposite direction. | |
| 465. |
The current flowing through the resistance R in the circuit in the figure has the form 2 cos 4, where R is |
| Answer» Inductor is not given, hence ignoring the inductance. Let I1 and I2 are currents in the loop then . | |
| 466. |
In a series RLC circuit excited by = E sin ω is seen that LC < 1/ω. Then |
| Answer» At frequencies less than resonant frequency current leads voltage. | |
| 467. |
A resistance R is connected to a voltage source V having internal resistance R. A voltmeter of resistance R is used to measure the voltage across R. The voltmeter will read |
| Answer» Effective resistance of R and Rm is The reading is . | |
| 468. |
Zinc oxide is a non-linear resistance. |
| Answer» It is used in lightning arresters due to its non-linear resistance property. | |
| 469. |
Three resistances of 15 Ω, 10 Ω and 3 Ω are connected in parallel. The overall resistance is |
| Answer» For resistances is parallel, overall resistance is less than the smallest resistance. | |
| 470. |
In figure, the switch is closed at = 0. At = 0 The value of current supplied by battery is |
| Answer» At t = 0, current in R-L branch is zero. | |
| 471. |
In the circuit shown in the figure the power dissipated in 30 Ω resistor will be maximum if the value of R is |
| Answer» If R = 0, it will be act a short circuit, 16 Ω Resistor will not play any role, only power dissipated in 30 Ω resistor. But it R = 0, then power dissipated in 16 Ω resistor also. | |
| 472. |
In an RLC underdamped circuit |
| Answer» | |
| 473. |
When a lead acid battery is being charged, the specific gravity of the electrolyte |
| Answer» Specific gravity of electrolyte is highest when battery is fully charged and is lowest when discharged. | |
| 474. |
Two sinusoidal voltage sources = 50 sin (100) and = 50 sin (100 + ) are connected in parallel and fed an inductance X = 2Ω. The cuirent through X is |
| Answer» Since voltages have a phase difference of 180°, current is zero. | |
| 475. |
In figure, the current after a long time after closing of switch is |
| Answer» At t = ∞ the circuit has effectively two 6Ω resistances in parallel. | |
| 476. |
In the network of the figure is the maximum power is delivered to RL if its value is |
| Answer» max power will be transfer, when RL is equal to internal resistance of voltage source then . | |
| 477. |
Energy = voltage x charge. |
| Answer» Energy = voltage x current x time = voltage x charge. | |
| 478. |
A T network is inserted between source and R as shown in figure. The resistance seen by the source remains the same with or without T network when R is |
| Answer» If R = 15 Ω resistance, seen by the source = . | |
| 479. |
The circuit shown in the figure has initial current (0) = 1A through the inductor and an initial voltage (0) = 1 V across the capacitor. For input () = U() the Laplace transform of the current () for ≥ 0 is |
| Answer» Apply KVL Vi(s) = I(s).R + Ls I(s) - Li(0+) + Put the given values and . | |
| 480. |
In figure, the time constant for the capacitor charging is |
| Answer» Effective resistence is . Hence RC = 6 μs. | |
| 481. |
In figure, the short circuit current through terminal AB will be |
| Answer» No current will flow through 2Ω resistance in parallel with short-circuit. | |
| 482. |
Permeability is analogous to |
| Answer» | |
| 483. |
A parallel RLC network has R = 4Ω, L = 4H, C = 0.25F. Then at resonance Q = |
| Answer» For parallel resonant circuit | |
| 484. |
A resistance and an inductance are connected in parallel and fed from 50 Hz ac mains. Each branch takes a current of 5 A. The current supplied by source is |
| Answer» The current is 5 - j5 = 52 + 52 = 7.07 A. | |
| 485. |
A coil is wound having a diameter . Its inductance is 10 mH. If it is rewound on the same core with a wire having diameter 0.5 and total weight of the wire is the same as before, the inductance will be |
| Answer» Since diameter is halved, area of cross-section is one-fourth. The number of turns becomes four times. Inductance = μ N2. | |
| 486. |
A two-port network is represented by ABCD parameters given byIf port is terminated by R, then input impedance seen at port 1 is given by |
| Answer» From transmission matrix V1 = AV2 - BI2 I/P impedance I1 = CV2 - DI2 Given V2 = - I2.R1 . | |
| 487. |
A series circuit having R = 3 Ω and L = 2 H is excited by a 10 V battery. At = 0, / is |
| Answer» | |
| 488. |
The transfer function of an R-L-C circuit given by The Quality factor (Q-factor) of this circuit is |
| Answer» . | |
| 489. |
An RC circuit initially at rest has a step signal. The response V() across C is V() = 1 - , If now there is an initial voltage on C of 2 volts for the same step signal, V() is now |
| Answer» At t = 0+, V0 = 4 volt. at t = ∞ C open Vf = 4 x 2 = 8 volt. | |
| 490. |
The minimum number of equations required to analyze the circuit shown in the figure is |
| Answer» No. of loop = No. of equations = b - n + 1 7 - 4 + 1 4. | |
| 491. |
If Z() has a pole at origin, the realization leads to |
| Answer» In such a function the denominator is one degree higher than the numerator. Therefore we get a term . Hence, the network has capacitance in series. | |
| 492. |
A series resonant circuit has inductance L. If L is increased, the resonant frequency |
| Answer» . As L increases ωr decreases. | |
| 493. |
In a coupled coil the primary has 100 turns and secondary has 200 turns. The primary produces, a flux Φ = . The coefficient of coupling is 1. The voltages induced in secondary is |
| Answer» | |
| 494. |
The ABCD parameters of ideal : 1 transformer shown in the figure are . The value of X will be |
| Answer» . | |
| 495. |
An RC driving point impedance function has zeros at = - 2 and = - 5. The admissible poles are |
| Answer» In RC functions poles and zeros are interlaced. | |
| 496. |
The current wave of figure, is passed through a 3 H inductor during the period 0 to 2 seconds |
| Answer» | |
| 497. |
A triangular Pulse of 10 V peak is applied to a capacitor of 0.4 F. The change of the capacitor and its waveform is |
| Answer» q = cv 0.4 x 10 4, triangular pulse. | |
| 498. |
A 10 μF capacitor is charged from a 5 volt source through a resistance of 10 kΩ. The charging current offer 35 m sec. If the initial voltage on C is - 3 V is |
| Answer» Initial current immediately after charging = i = i0e-t/RC 0.8 mA x 0.8 x 10-3 0.56 mA. | |
| 499. |
If an admittance Y() has a term K, the realization would give |
| Answer» Admittance of a capacitance K is Ks. | |
| 500. |
If the diameter of a wire is doubled, the current carrying capacity of the wire becomes |
| Answer» Since diameter is doubled, area of cross-section becomes four times. Current carrying capacity is proportional to area of cross-section. | |