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.
| 1. |
In the circuit of figure is |
| Answer» I3 is inductive current and must lag I2 which is capacitive current. | |
| 2. |
The V at terminals A and B is equal to |
| Answer» Apply KVL to loop 1 5V - 3I1 - 2 (I1 - I2) - 5V = 0 ∴ I2 = 0 5V - 5V - 5I1 = 0 I1 = 0 ∴ VAB = 5 volt. | |
| 3. |
If A = 3 + 1 and B = 4 + 3, A - B = |
| Answer» A - B = - 1 - j2 = 2.236∠243.43°. | |
| 4. |
Two impedances 10 - 10 and 10 + 10 are connected in parallel. Their combined impedance is |
| Answer» | |
| 5. |
Resistivity of semiconductors is around 100 Ω-m. |
| Answer» Resistivity of semiconductors is about 1 ohm-m. | |
| 6. |
Two capacitors of 20 μF each are in series. The total capacitance is |
| Answer» | |
| 7. |
Thevenin's theorem is used to find current in a branch of a network. It is now desired to find current in another branch of the network |
| Answer» Thevenin's equivalent circuit with respect to particular terminals only. | |
| 8. |
A series resonant circuit has R = 2 Ω, L = 0.1 H and C =10 μF. At resonance applied voltage = 10 ∠0 V. Voltage across inductance is likely to be |
| Answer» Voltage across inductance = QV and leads the applied voltage. | |
| 9. |
The admittance parameter Y in the 2 port network in the figure |
| Answer» I1 = y11 V1 + y12 V2 y12 = V1 = 0 If V1 = 0 then y12 = 0.1 mho. | |
| 10. |
The differential equation for the current () in the Ckt is |
| Answer» Apply KVL . | |
| 11. |
The circuit in figure, the switched on at = 0. After a long time the current through 5 Ω resistance is |
| Answer» At t = ∞ inductance behaves as short-circuit. | |
| 12. |
In the circuit of figure the current through 5 Ω resistance at = ∞ is |
| Answer» The 5 ohm resistance is short-circuited by inductance. | |
| 13. |
In an infinite ladder Ckt as shown above each resistance of Ω then R |
| Answer» Let RAB = R R = r + r || R R = 1.61r. | |
| 14. |
A 20 Ω resistor, a 1H inductor and 1μF capacitor are connected in parallel the combination is driven by a unit step current. Under the steady state, source current flows through |
| Answer» Under steady state, C will be open, Inductor short circuit hence resistance will be shorted out, due to low reactance path current will now due to inductor only. | |
| 15. |
A series resonant circuit has parameters 10 ω, 1 H and 0.1 F. It is excited by a voltage = 100 sin ω. At resonant frequency, the power dissipated in the circuit is |
| Answer» | |
| 16. |
Cells are connected in series to increase |
| Answer» When cells are in series, current remains the same but voltage increases. | |
| 17. |
The low pass filter characteristic shown in figure realizable. |
| Answer» It is not realizable. | |
| 18. |
If sequence currents I = 2 ∠- 90°, I = 0.2 ∠ 90° and I = 1.8 ∠ 90°, I = |
| Answer» Ia = Ia1 + Ia2 + Ia0 = 2∠-90 + 0.2∠90 + 1.8∠90° = 2∠-90° + 2∠90° = 0. | |
| 19. |
For the R-L circuit shown in the figure, the input voltage () = U(). The current () is |
| Answer» Vi(s) = 1/s at t = ∞ i(t) = 1/2 = 0.5 . | |
| 20. |
If () = - (- ) and () satisfies Dirichlet conditions, then () can be expanded in Fourier series having |
| Answer» Since f(-t) = -f(t) only sine terms exist. | |
| 21. |
A parallel plate capacitor has plate area A and distance between the plates is . It has two dielectrics each of thickness and area 0.5 A. The dielectric constants are ∈ and ∈. The total capacitance is given by the equation |
| Answer» The combination is equal to two capacitors in parallel. | |
| 22. |
In figure, the switch is closed at = 0 when current through inductor is 6 A, the rate of change of current through resistor is 6 A/s. The value of L is |
| Answer» i = 18(1 - et/L) = 6; . Therefore, L = 2H. | |
| 23. |
In figure, the switch is closed at = 0. At = 0, / = 4 A/s. Then V = |
| Answer» | |
| 24. |
If V = 10 ∠0, V = 10 ∠ -120° and V = 10 ∠ -240°, then V and V are |
| Answer» Since it is a balanced system of voltages, Va2 and Va0 must be zero. | |
| 25. |
A wire has a diameter and resistance R. If the diameter is made 3, the length and material remaining the same, the new value of resistance will be |
| Answer» Since diameter is 3d, area of cross-section is increased 9 times. Therefore, resistance is R/9. | |
| 26. |
The realization of a reactance function gives |
| Answer» Both XL and XC are reactances. | |
| 27. |
The correct relation between energy and charge is |
| Answer» Energy = V x I x t since I x t = Q, energy = voltage x charge. | |
| 28. |
In figure V is ideal voltmeter having infinite resistance. It will read __________ volt. |
| Answer» | |
| 29. |
The equivalent inductance seen at terminals A - B is |
| Answer» | |
| 30. |
For the lattice circuit shown in the figure Z = 2 Ω and Z = 2 Ω. The values of the open circuit impedance parameters Z = are |
| Answer» Z parameter equations are V1 = I1 Z11 + I2 Z12 V2 = I1Z21 + I2Z22 . | |
| 31. |
The correct relation between joules and calories is |
| Answer» Calories and joules are related by J, i.e., mechanical equivalent of heat. | |
| 32. |
The filter in figure, uses ideal op-amp. It is |
| Answer» Capacitor in shunt gives low pass filter. | |
| 33. |
For a rectified sinusoidal wave clipped at 0.707 its peak value (figure), the average value is |
| Answer» | |
| 34. |
A voltage = 100 sin (100 + 45°) V is applied to an impedance 10 + 10 ohm. The current is |
| Answer» Z = 200∠45°Ω ; | |
| 35. |
Two coils are connected in parallel. Their fluxes are adding. If the connections of one of the coils are reversed, the total inductance of the arrangement |
| Answer» Mutual inductance term will become negative. | |
| 36. |
The graph of a network has 6 branches with 3 tree branches. The minimum number of equations required for solution of network is |
| Answer» Three tree branches mean 3 loops and hence 3 equations. | |
| 37. |
In figure, S is closed at = 0. At = , I = 1 A and / = 1 A/s. Then the value of L is |
| Answer» i = 18(1 - e-t/L) = 6 and Hence L = 2H. | |
| 38. |
In the circuit of figure, the switch is closed at = 0. At = 0 the current supplied by battery is |
| Answer» Current through an inductance cannot change instantaneously. | |
| 39. |
The current wave in figure is passed through 3 H inductor. The voltage across inductance during the period 2 < < 3 seconds is |
| Answer» | |
| 40. |
In figure, the charge on 0.8 μF capacitor is |
| Answer» Each of parallel combination of capacitors is equal to 1 μF. Therefore, voltage across each capacitor is 50 V. Q = 0.8 x 50 = 40 μC. | |
| 41. |
The equivalent unit of joule is |
| Answer» Both joule and Newton-metre are units of energy. | |
| 42. |
Maximum power transfer theorem finds application in |
| Answer» In power and distribution circuits efficiency has to be very high. | |
| 43. |
In a series L-C circuit fed by ac voltage, voltage drops across L and C are 40 V and 30 V respectively. The supply voltage is |
| Answer» |V| = IXL - IXC. | |
| 44. |
In a reactance function |
| Answer» Only then the network has only L and C. If poles and zeros are not on jω axis, resistance will be there. | |
| 45. |
A two branch parallel tuned circuits has a coil of resistance R and inductance L in one branch and capacitance C in the second branch. The bandwidth is 200 radians/sec. A load of resistance R is connected in parallel. The new bandwidth will be |
| Answer» Loading increases bandwidth of parallel tuned circuii. | |
| 46. |
Three identical coils each having self inductance L are connected in series so that the fluxes of all the three are in the same direction. If mutual inductance between each pair of coils is M, the total inductance of the arrangement is |
| Answer» Total inductance = L + L + L + M + M + M + M + M + M = 3L + 6M. | |
| 47. |
Two 2 port circuits are connected cascaded. To determine the response, it is more convenient to use |
| Answer» ABCD matrix of two-four terminal network is the product of individual ABCD matrices. | |
| 48. |
In the circuit of figure. The current supplied by battery at = ∞ is |
| Answer» At t = ∞, inductance is short-circuited and capacitor is open circuited. | |
| 49. |
The natural frequency S of the given circuit is |
| Answer» [When current open and seen from inductance side] Sn + 1 = 0 Sn = -1. | |
| 50. |
For addition and subtraction operations, phasors |
| Answer» Addition and subtraction is not possible in polar form. | |