MCQOPTIONS
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MCQOPTIONS
This section includes 1800 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 451. |
The differential equation for the current i(t) in the Ckt is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 452. |
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. | 0.3 H/500 |
| D. | none of the above |
| Answer» E. | |
| 453. |
A periodic voltage v(t) = 1 + 4 sin ωt + 2 cos ωt is applied across a 1 ohm resistance. The power dissipated is |
| A. | 1 W |
| B. | 11 W |
| C. | 21 W |
| D. | 24.5 W |
| Answer» C. 21 W | |
| 454. |
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 |
| Answer» B. CE | |
| 455. |
When R and L are connected in parallel, R > |Z|. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 456. |
The colour coding of a resistors shows 100 K, ± 10%. When the resistance was measured with an ohmmeter, it read |
| A. | 95 K |
| B. | 80 K |
| C. | 120 K |
| D. | 85 K |
| Answer» B. 80 K | |
| 457. |
The relative permeability of an iron specimen is 400 when B = 0.2 T. If B = 0.4 T, μᵣ will be |
| A. | 400 |
| B. | less than 400 |
| C. | more than 400 |
| D. | more or less than 400 |
| Answer» E. | |
| 458. |
A system function given by the following equation, the resonant frequency in rad/sec and bandwidth in rad/sec is given by |
| A. | 5, 10 |
| B. | 5, 4 |
| C. | 10, 4 |
| D. | 10, 10 |
| Answer» D. 10, 10 | |
| 459. |
For an RLC series circuit, Z(s) will be of the form of |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 460. |
The frame of an electric motor is earthed through three earthing plates resistances 30 Ω, 20 Ω and 10 Ω respectively. During fault the energy dissipated by three plates are W1, W2 and W3. Then |
| A. | W1 > W2 > W3 |
| B. | W1 < W2 < W3 |
| C. | W1 = W2 = W3 |
| D. | W1 + W3 < W2 |
| Answer» C. W1 = W2 = W3 | |
| 461. |
For the following circuit a source of V1(t) = e^(-2t) is applied, then the resulting response V2(t) is given by |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 462. |
The following equation where v1, v2 ... vb are the instantaneous branch voltages and i1, i2 ... ib are the instantaneous branch currents pertains to |
| A. | Compensation theorem |
| B. | Bisectional theorem |
| C. | Tellegen's theorem |
| D. | Reciprocity theorem |
| Answer» D. Reciprocity theorem | |
| 463. |
The input resistance of the network in figure is |
| A. | 1.5 R |
| B. | 13R/8 |
| C. | 34R/21 |
| D. | 89R/55 |
| Answer» E. | |
| 464. |
Assertion (A): When capacitor is fed by a dc voltage given a capacitor behaves as short circuit at t = 0 and open circuit at f = ∞.Reason (R): The impedance of a capacitor is 1/Sc |
| 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 |
| Answer» B. Both A and R are true and R is not the correct explanation of A | |
| 465. |
In a series RLC circuit, the current at resonance is I₀ the total energy stored in the circuit at resonance is |
| A. | LI₀² |
| B. | 2 LI₀² |
| C. | √2 LI₀² |
| D. | 0.5 LI² |
| Answer» B. 2 LI₀² | |
| 466. |
The circuit in figure, is to be scaled to an impedance level of 5kΩ and resonant frequency of 5 x 10⁶ rad/sec. The possible combination of R, L, C is |
| A. | 2.5Ω, 0.2 mH, 200 pF |
| B. | 5 kΩ, 0.2 mH, 200 pF |
| C. | 5 kΩ, 0.2 mH, 200 μF |
| D. | 5 kΩ, 0.1 mH, 0.4 μF |
| Answer» C. 5 kΩ, 0.2 mH, 200 μF | |
| 467. |
Two capacitors of 20 μF each are in series. The total capacitance is |
| A. | 5 μF |
| B. | 10 μF |
| C. | 40 μF |
| D. | 400 μF |
| Answer» C. 40 μF | |
| 468. |
A dc network has an open circuit voltage of 5 V. When its terminals are short circuited a current of 5 A flows through the short circuit. If the short circuit is removed and a resistance of 1.5 Ω is connected across its terminals, the current will be |
| A. | 1 A |
| B. | 2 A |
| C. | 2.5 A |
| D. | 5 A |
| Answer» C. 2.5 A | |
| 469. |
If Va = 10 ∠0, Vb = 10 ∠ -120° and Vc = 10 ∠ -240°, then Va2 and Va0 are |
| A. | 10 and 0 respectively |
| B. | 0 and 10 respectively |
| C. | 0 and 0 |
| D. | 10 and 10 |
| Answer» B. 0 and 10 respectively | |
| 470. |
An RC series circuit has R = 20 Ω and XC = 20 Ω. Then Z = |
| A. | 40 Ω |
| B. | 28.28 Ω |
| C. | 20 Ω |
| D. | 1 Ω |
| Answer» C. 20 Ω | |
| 471. |
A coil has a resistance of 2 Ω and inductance of 0.1 mH. The applied voltages is suddenly increased from 10 V to 20 V. After steady state condition have reached, the current is |
| A. | 2 A |
| B. | more than 2 A but less than 4 A |
| C. | 4 A |
| D. | more than 4 A |
| Answer» D. more than 4 A | |
| 472. |
The frequency at which maximum voltage occurs across the inductance in R-L-C series circuit is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 473. |
A series R, L, C circuit has R = 2Ω, L = 1H, C = 1 μF. It is connected to an ac variable frequency source of peak voltage 10 V. At resonance the power supplied by the source will be |
| A. | 50 Ω |
| B. | 25 Ω |
| C. | 12.5 Ω |
| D. | 6.25 Ω |
| Answer» C. 12.5 Ω | |
| 474. |
If A = 7 ∠15, A² is |
| A. | 49 ∠225° |
| B. | 49 ∠30° |
| C. | 49 ∠15° |
| D. | 49 ∠7.5° |
| Answer» C. 49 ∠15° | |
| 475. |
In terms of ABCD parameters, the image parameter Z11 is equal to |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» D. D | |
| 476. |
A parallel plate capacitor has plate area A and distance between the plates is d. It has two dielectrics each of thickness d and area 0.5 A. The dielectric constants are ∈1 and ∈2. The total capacitance is given by the equation |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» B. B | |
| 477. |
A resistor R of 1 Ω and two inductor L1 and L2 of inductances 1 H and 2 H respectively, are connected in parallel. At some time, the current through L1 and L2 are 1 A and 2 A, respectively. The current through R at time t = ∞ will be |
| A. | zero |
| B. | 1 A |
| C. | 2 A |
| D. | 3 A |
| Answer» B. 1 A | |
| 478. |
Two voltages 50 V each have a phase difference of 45°. The rms value of resultant sum of the two voltages is |
| A. | 70.7 V |
| B. | 80.4 V |
| C. | 92.4 V |
| D. | 100 V |
| Answer» D. 100 V | |
| 479. |
Consider the following statements: |
| 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 |
| Answer» C. A is true but R is false | |
| 480. |
If Fourier transform of f(t) is F(jω), then which pairs of time functions and Fourier transforms are matched. Select the answer using the following codes |
| A. | 1 and 2 |
| B. | 1 and 3 |
| C. | 2 and 3 |
| D. | 1, 2 and 3 |
| Answer» B. 1 and 3 | |
| 481. |
In an ac network the sum of currents entering a node is 10 ∠45°. The sum of currents leaving the node is |
| A. | 19.32 ∠45° |
| B. | 15 ∠45° |
| C. | 20 ∠45° |
| D. | zero |
| Answer» B. 15 ∠45° | |
| 482. |
Assertion (A): The Laplace transform of a ramp is 1/s².Reason (R): The integral of a unit step function gives an impulse function. |
| 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 |
| Answer» D. A is false but R is true | |
| 483. |
The pass band of a constant k filter with Z1 and Z2 as series and shunt arm impedances is given by |
| A. | A |
| B. | B |
| C. | c |
| D. | D |
| Answer» B. B | |
| 484. |
The transfer function H(s) of a system is given by following equation. Given that understeady state conditions, the sinusoidal I/P and 0/P are respectively x(t) = cos 2t and y(t) = cos (2t + Φ), then the angle Φ will be |
| A. | 45° |
| B. | 0° |
| C. | -45° |
| D. | -90° |
| Answer» D. -90° | |
| 485. |
In the circuit shown in figure the inductor current and capacitor voltage are given at a time t. At this instant i is __________ A and di/dt is __________ A/sec. |
| A. | -5 A, 10 V |
| B. | 5 A, 50 V |
| C. | 2.5, 25 |
| D. | 0, ∞ |
| Answer» B. 5 A, 50 V | |
| 486. |
For a series RLC circuit bandwidth is ω2 - ω₁ = R/2L. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 487. |
A two branch parallel resonant circuit has a coil of resistance R and inductance L, in one branch and a capacitors C in the other branch. The source voltage is V, At resonance the circulating current is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» E. | |
| 488. |
The circuit is figure, is in steady state with switch closed. At t = 0 switch is opened. The current i is |
| A. | A |
| B. | B |
| C. | C |
| D. | D |
| Answer» C. C | |
| 489. |
An ac voltage 20 sin 1000t feeds an R-C series circuit. R = 8 Ω and active power is 4 W. The power factor is |
| A. | 1 |
| B. | 0.8 |
| C. | 0.6 |
| D. | 0.4 |
| Answer» E. | |
| 490. |
In the circuit of figure the current through 3 Ω resistance at t = ∞ is |
| A. | 4 A |
| B. | 2.5 A |
| C. | 3.1 A |
| D. | 0 |
| Answer» C. 3.1 A | |
| 491. |
Wave A starts its positive half cycle at ωt = 30° and wave B starts its positive half cycle at ωt = 75° then wave B is leading wave A by 45°. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |
| 492. |
The circuit shown in the figure, with R = 1/3 Ω, L = 1/4H, C = 3F has input voltage v(t) = sin2t. The resulting current i(t) is |
| A. | 5 sin (2t + 53.1°) |
| B. | 5 sin (2t - 53.1°) |
| C. | 25 sin (2t + 53.1°) |
| D. | 25 sin (2t - 53.1°) |
| Answer» B. 5 sin (2t - 53.1°) | |
| 493. |
An RLC series circuit has R = 8 Ω, XL = 8 Ω and XC = 8 Ω Its impedance is |
| A. | 8 + j 16 Ω |
| B. | 8 + j 8 Ω |
| C. | 8 Ω |
| D. | 24 Ω |
| Answer» D. 24 Ω | |
| 494. |
In the circuit of figure the current through 3 Ω resistance at t = 0+ is |
| A. | 4 A |
| B. | 2.5 A |
| C. | 3.1 A |
| D. | 0 |
| Answer» E. | |
| 495. |
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° |
| Answer» C. the current leads the voltage by about 84° | |
| 496. |
A resistance of 5 ohms is connected in one branch of a network. The current in this branch is 2.2. A. If the resistance is increased to 7.5 Ω, the remaining circuit being the same, the current in this branch will be |
| A. | 2.2 A |
| B. | less than 2.2 A |
| C. | 2.2 A or less than 2.2 A |
| D. | 2.2 A or less or more than 2.2 A |
| Answer» C. 2.2 A or less than 2.2 A | |
| 497. |
A parallel RLC network has R = 4Ω, L = 4H, C = 0.25F. Then at resonance Q = |
| A. | 1 |
| B. | 10 |
| C. | 20 |
| D. | 40 |
| Answer» B. 10 | |
| 498. |
Consider the following two statements: |
| 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 |
| Answer» C. A is true but R is false | |
| 499. |
If A = 3 + j1, A⁴ |
| A. | 100 ∠18.43° |
| B. | 100 ∠73.72° |
| C. | 10 ∠18.43° |
| D. | 10 ∠73.72° |
| Answer» C. 10 ∠18.43° | |
| 500. |
The terms RMS and average values apply only to sine waves. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | Can't say |
| Answer» C. May be True or False | |