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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.
| 51. |
In the circuit shown in the figure the power dissipated in 30 Ω resistor will be maximum if the value of R is |
| A. | 30 Ω |
| B. | 10 Ω |
| C. | 9 Ω |
| D. | zero |
| Answer» E. | |
| 52. |
In the figure circuit, V1 = 40 V. When R is 10 Ω. When R is zero, the value of V2 will be |
| A. | 40 V |
| B. | 30 V |
| C. | 20 V |
| D. | 10 V |
| Answer» B. 30 V | |
| 53. |
The hot resistance of a tungsten lame is about 12 times its cold resistance. Accordingly, the cold resistance of a 60 Ω, 120 V lamp is about __________ ohm. |
| A. | 5 |
| B. | 240 |
| C. | 2 |
| D. | 2880 |
| Answer» D. 2880 | |
| 54. |
Two wires A and B have the same cross-section area and are made of the same material. RA = 600 Ω and RB = 100 Ω. The number of times A is longer than B is |
| A. | 6 |
| B. | 2 |
| C. | 4 |
| D. | 5 |
| Answer» B. 2 | |
| 55. |
When a 10 K, 10%, 1/4 Ω resistor is connected in series with a 12 K, ± 1%, 1/4 Ω resistor, the resulting combination has the following specifications |
| A. | 22 K, ± 11%, 1/2 Ω |
| B. | 22 K, ± 5.5%, 1/2 Ω |
| C. | 22 K, ± 5.5%, 1/8 Ω |
| D. | none of these |
| Answer» C. 22 K, ± 5.5%, 1/8 Ω | |
| 56. |
In figure, a voltmeter of internal resistance 1200 Ω is connected across 600 Ω resistance and it reads 5 V. The value of R is |
| A. | 1200 Ω |
| B. | 2400 Ω |
| C. | 3600 Ω |
| D. | 7200 Ω |
| Answer» C. 3600 Ω | |
| 57. |
If e = 110 sin (ωt + p/3) and i = 5 sin (ωt - p/3), the impedance of the circuit is |
| A. | 22 Ω |
| B. | 16 Ω |
| C. | 30.8 Ω |
| D. | 11 Ω |
| Answer» B. 16 Ω | |
| 58. |
In a series RLC circuit excited by e = Em sin ωt is seen that LC < 1/ω2. Then |
| A. | I lags E |
| B. | I leads E |
| C. | I leads E are in phase |
| D. | voltage across L and C are equal |
| Answer» C. I leads E are in phase | |
| 59. |
Current having waveform in figure flows through 10 Ω resistance. Average power is |
| A. | 1000 W |
| B. | 500 W |
| C. | 333.3 W |
| D. | 250 W |
| Answer» D. 250 W | |
| 60. |
In low pass filter of figure R0 = 1 Ω and cut off frequency is 1 rad/sec. The values of L and C are |
| A. | 1 H and 2 F |
| B. | 1 H and 1 F |
| C. | 2 H and 1 F |
| D. | 1 H and 2 F |
| Answer» E. | |
| 61. |
For the network in figure, which of the following expressions gives the value of net inductance between terminals A and B L1 ± L2L1 ± L2 ± ML1 ± L2 - 2ML1 ± L2 ± 2M Select the answer using the following codes |
| A. | 1 only |
| B. | 1 and 2 |
| C. | 3 and 4 |
| D. | 2 and 4 |
| Answer» C. 3 and 4 | |
| 62. |
An RLC series circuit has R = 1 Ω, L = 1 H, C = 1 F. The damping ratio is |
| A. | More than 1 |
| B. | 1 |
| C. | 0.5 |
| D. | Zero |
| Answer» D. Zero | |
| 63. |
The y parameters of a four terminal network are . A one ohm resistance is connected as shown in figure. The new y parameters are |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» B. [B]. | |
| 64. |
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 |
| Answer» E. | |
| 65. |
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 |
| Answer» B. 1 and 4 | |
| 66. |
For a voltage transfer function H(s), realizable by RLC network, the following statements are made H(s) cannot have a pole at s = 0H(s) cannot have a pole at s = ± j4H(s) cannot have a pole at s = ∞H(s) cannot have a pole at s = + 2 Of these statements |
| A. | 3 and 4 are correct |
| B. | 2 and 4 are correct |
| C. | 1 and 2 are correct |
| D. | 1 and 3 are correct |
| Answer» B. 2 and 4 are correct | |
| 67. |
A step voltages is applied to RLC series circuit having R = 2 Ω, L = 1 H and C = 1 F. The transient current response will be |
| A. | over damped |
| B. | critically damped |
| C. | under damped |
| D. | any of the above depending the magnitude of voltage |
| Answer» C. under damped | |
| 68. |
In figure, the current through 2 Ω resistance is |
| A. | zero |
| B. | -2A |
| C. | 2A |
| D. | 1A |
| Answer» B. -2A | |
| 69. |
Consider the following units sec-1rad2/sec2secΩ The units of , RC and are respectively |
| A. | 1, 2, 4, 3 |
| B. | 3, 2, 1, 4 |
| C. | 2, 4, 1, 3 |
| D. | 1, 2, 3, 4 |
| Answer» E. | |
| 70. |
A delta connection contains three impedances of 60 Ω each. The impedances of equivalent star connection will be |
| A. | 15 Ω |
| B. | 20 Ω |
| C. | 30 Ω |
| D. | 40 Ω |
| Answer» C. 30 Ω | |
| 71. |
A magnetic circuit has an iron length of 20 cm and air gap length 0.1 cm. If μr = 200 then |
| A. | mmf for iron and air gap are equal |
| B. | mmf for iron is much less than that for air gap |
| C. | mmf for iron is much more than that for air gap |
| D. | either (a) or (c) |
| Answer» B. mmf for iron is much less than that for air gap | |
| 72. |
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 | |
| 73. |
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 | |
| 74. |
If Fourier transform of f(t) is F(jω), then which pairs of time functions and Fourier transforms are matched f (t + 2) - ej2ω F(jω)f (-0.5t) - 2F (-2jω) - 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 | |
| 75. |
The Thevenin's equivalent of network in figure(1) is a 10 V source in series with 2 Ω resistance. If a 3 Ω resistance is connected across AB as shown in figure(2) the Thevenin's equivalent is |
| A. | 10 V in series with 1.2 Ω resistance |
| B. | 6 V in series with 1.2 Ω resistance |
| C. | 10 V in series with 5 Ω resistance |
| D. | 6 V in series with 5 Ω resistance |
| Answer» C. 10 V in series with 5 Ω resistance | |
| 76. |
A battery charger can drive a current of 5A with 1Ω resistance connected at its output. If it can charge 2 V battery at 7 A rate, its Thevenin's equivalent circuit will be |
| A. | 7.5 in series with 0.5 Ω resistance |
| B. | 1.25 V in series with 1.5 Ω resistance |
| C. | 7.5 V in parallel with 0.5 Ω resistance |
| D. | 12.5 V in parallel with 1.5 Ω resistance |
| Answer» B. 1.25 V in series with 1.5 Ω resistance | |
| 77. |
The RLC circuit for driving point admittance function is |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» D. [D]. | |
| 78. |
If figure, I = 2A if R = 20 Ω. When R = 10 Ω current I is |
| A. | 1 A |
| B. | 2 A |
| C. | 2.5 A |
| D. | 3 A |
| Answer» C. 2.5 A | |
| 79. |
If figure, power dissipated in 30Ω resistance will be maximum when value of R = |
| A. | 30 Ω |
| B. | 16 Ω |
| C. | 9 Ω |
| D. | zero |
| Answer» D. zero | |
| 80. |
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 |
| Answer» D. 0.125 A | |
| 81. |
In figure, . The values of C and R are |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» B. [B]. | |
| 82. |
In figure, V1 = 40 V when R = 10 Ω, if R = 0, V2 will be |
| A. | 40 V |
| B. | 30 V |
| C. | 20 V |
| D. | 10 V |
| Answer» D. 10 V | |
| 83. |
In figure, power in 6 Ω resistor is zero then V = |
| A. | 202∠45° |
| B. | 20 ∠30° |
| C. | 20 ∠45° |
| D. | 202∠30° |
| Answer» B. 20 ∠30° | |
| 84. |
Which of the following theorems can be conveniently used to find power consumed in 10 Ω resistor in figure? |
| A. | Thevenin theorem |
| B. | Maximum power transfer theorem |
| C. | Millman's theorem |
| D. | Superposition theorem |
| Answer» E. | |
| 85. |
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 |
| Answer» B. 1.25 A | |
| 86. |
If sequence currents Ia1 = 2 ∠- 90°, Ia2 = 0.2 ∠ 90° and Ia3 = 1.8 ∠ 90°, Ia = |
| A. | 0 |
| B. | 1 |
| C. | 4 |
| D. | 8 |
| Answer» D. 8 | |
| 87. |
If operator 'a' = 1 ∠120° then (1 - a2) = |
| A. | 1 ∠ - 30° |
| B. | 1 ∠ 30° |
| C. | 1 ∠ - 60° |
| D. | 1 ∠60° |
| Answer» B. 1 ∠ 30° | |
| 88. |
If operator 'a' = 1 ∠120° then (1 + a + a2) = |
| A. | -a |
| B. | -a2 |
| C. | 1 |
| D. | 0 |
| Answer» E. | |
| 89. |
If operator 'a' = 1 ∠120° then (1 + a2) = |
| A. | 3 |
| B. | 3 ∠30° |
| C. | 3 ∠ - 30° |
| D. | 3 ∠60° |
| Answer» B. 3 ∠30° | |
| 90. |
For a network having 1 Ω resistor and 1 F capacitor in series Z(s) = |
| A. | [A]. |
| B. | [B]. |
| C. | 1 + s |
| D. | [D]. |
| Answer» B. [B]. | |
| 91. |
An impedance function has term . The realizations would give |
| A. | an inductance of value 2K2/ω22 |
| B. | a capacitance of value 2K2/ω22 |
| C. | an inductance 2K2/ω22 and capacitance in parallel |
| D. | none of the above |
| Answer» D. none of the above | |
| 92. |
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 | |
| 93. |
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 |
| A. | 10 ∠0 V |
| B. | 10 ∠45° V |
| C. | 100 ∠90° V |
| D. | 100 ∠-90° V |
| Answer» D. 100 ∠-90° V | |
| 94. |
A resistance R, inductance L and capacitance C are in series. The source frequency is adjusted to be equal to resonant frequency. The lower half power frequency is ω1. Another resistance R is added in series with the circuit. The new lower half power frequency will be |
| A. | ω1 |
| B. | less than ω1 |
| C. | more than ω1 |
| D. | either more than ω1 or less then ω1 |
| Answer» D. either more than ω1 or less then ω1 | |
| 95. |
A series resonant circuit has R = 10 Ω, L = 1 μH and C = 1 mF. If R is increased to 20 Ω the resonant frequency |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | may increases or decreases |
| Answer» D. may increases or decreases | |
| 96. |
In a series resonant circuit Q is more than 10. Then the lower half power frequency ω1, and resonant frequency ω0 are related as |
| A. | ω1 = ω0 + bandwidth |
| B. | ω1 = ω0 + 0.5 (bandwidth) |
| C. | ω1 = ω0 - 0.5 (bandwidth) |
| D. | ω1 = ω0 + bandwidth |
| Answer» D. ω1 = ω0 + bandwidth | |
| 97. |
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 |
| Answer» D. more than 10000 rad/sec | |
| 98. |
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, the dynamic resistance is |
| A. | 1 Ω |
| B. | 10 Ω |
| C. | 100 Ω |
| D. | more than 100 Ω |
| Answer» E. | |
| 99. |
A two branch parallel tuned circuit has 100 Ω resistance and 0.1 H inductance in one branch and 10-6 F capacitor in the other. At resonance frequency, the dynamic resistance is |
| A. | 10 Ω |
| B. | 100 Ω |
| C. | 1000 Ω |
| D. | 10000 Ω |
| Answer» D. 10000 Ω | |
| 100. |
In a coupled coil the primary has 100 turns and secondary has 200 turns. The primary produces, a flux Φ = e-t. The coefficient of coupling is 1. The voltages induced in secondary is |
| A. | 200 e-t V |
| B. | 200 et V |
| C. | 200 V |
| D. | none of the above |
| Answer» B. 200 et V | |