MCQOPTIONS
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MCQOPTIONS
This section includes 571 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. |
If M is mutual inductance between fixed and moving coils and θ is deflection of dynamometer instrument, then |
| A. | [A]. |
| B. | θ ∝ M |
| C. | [C]. |
| D. | θ ∝ M2 |
| Answer» B. θ ∝ M | |
| 52. |
In a ballistic galvanometer, a charge of 100 μC gives a first swing of 25°. The charge required to cause first swing of 50° is |
| A. | 200 μC |
| B. | 400 μC |
| C. | 50 μC |
| D. | 25 μC |
| Answer» C. 50 μC | |
| 53. |
For critical damping, the resistance in D'Arsonval galvanometer circuit should be equal to |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» B. [B]. | |
| 54. |
The damping ratio, in D'Arsonval galvanometer is equal to |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | [D]. |
| Answer» C. [C]. | |
| 55. |
If C is spring constant and θ is deflection, controlling torque is |
| A. | Cθ |
| B. | C/θ |
| C. | θ/C |
| D. | C2θ |
| Answer» B. C/θ | |
| 56. |
Two ammeters A and B are connected in parallel in a circuit carrying 100 A. Their resistances are 0.8 mΩ. Their readings will be. |
| A. | 55.56 and 44.44 A respectively |
| B. | 44.44 A and 55.56 A respectively |
| C. | 60 A and 40 A respectively |
| D. | 40 A and 60 A respectively |
| Answer» B. 44.44 A and 55.56 A respectively | |
| 57. |
If a shunt of 200 Ω resistance is used with a galvanometer of 1000 Ω resistance, the multiplying power is |
| A. | 6 |
| B. | 5 |
| C. | 1/5 |
| D. | 1/6 |
| Answer» B. 5 | |
| 58. |
An ammeter has a resistance of 50 ohms and a shunt of 0.01 Ω. The deflection is θ. If the shunt resistance is increased to 0.02 Ω, the deflection will be. |
| A. | θ |
| B. | 2θ |
| C. | 0.5θ |
| D. | 0.25θ |
| Answer» C. 0.5θ | |
| 59. |
The coil of a moving iron instrument has a resistance of 500 Ω and an inductance of 1 H. It reads 250 V when a 250 V dc is applied. If series resistance is 2000 Ω, its reading when fed by 250 V, 50 Hz ac will be |
| A. | 260 V |
| B. | 252 V |
| C. | 250 V |
| D. | 248 V |
| Answer» E. | |
| 60. |
A sinusoidal ac voltage of amplitude 100 V is applied to a rectifying device which offers 10 Ω resistance in forward direction and infinite resistance in backward direction. A moving coil ammeter is also connected in the circuit. The reading of ammeter will be |
| A. | 10 A |
| B. | 5 A |
| C. | 3.185 A |
| D. | 14.14 A |
| Answer» D. 14.14 A | |
| 61. |
A sinusoidal ac voltage of amplitude 100 V is applied to a rectifying device which offers 10 Ω resistance in forward direction and infinite resistance in reverse direction. The reading on hot wire ammeter will be |
| A. | 10 A |
| B. | 5 A |
| C. | 3.185 A |
| D. | 1.414 A |
| Answer» C. 3.185 A | |
| 62. |
The resistance of a dc galvanometer is 20 Ω. A current of 10 mA causes full scale deflection. To convert it into 0-300 V voltmeter, we have to use a series resistance of |
| A. | 30000 Ω |
| B. | 29980 Ω |
| C. | 6000 Ω |
| D. | 15 Ω |
| Answer» C. 6000 Ω | |
| 63. |
A meter coil has a resistance of 100 Ω and a full scale deflection current of 10 mA. To convert it into a voltmeter of 0-200 V range, the series resistance should be |
| A. | 20 kΩ |
| B. | 19.9 kΩ |
| C. | 1.9 kΩ |
| D. | 20.1 kΩ |
| Answer» C. 1.9 kΩ | |
| 64. |
A moving coil instrument has a resistance of 0.5 Ω and a full scale deflection of 0.1 A. To convert it into an ammeter of 0-10 A the shunt resistance should be |
| A. | 0.004 Ω |
| B. | 0.005 Ω |
| C. | 0.05 Ω |
| D. | 0.1 Ω |
| Answer» C. 0.05 Ω | |
| 65. |
A meter with a resistance of 100 Ω and a full scale deflection of current of 1 mA is to be converted into voltmeter of 0 - 5 V range. The multiplier resistance should be |
| A. | 490 Ω |
| B. | 5000 Ω |
| C. | 4900 Ω |
| D. | 5100 Ω |
| Answer» D. 5100 Ω | |
| 66. |
A meter has a resistance of 1 Ω and full scale deflection current of 1 mA. To convert into an ammeter of 1 A range, the shunt resistance should be |
| A. | 1000 Ω |
| B. | 1 Ω |
| C. | 0.01 Ω |
| D. | 0.001 Ω |
| Answer» E. | |
| 67. |
A moving coil instrument has a resistance of 0.6 Ω and full scale deflection at 0.1 A. To convert it into an ammeter of 0-15 A range, the resistance of shunt should be |
| A. | 0.6 Ω |
| B. | 0.06 Ω |
| C. | 0.1 Ω |
| D. | 0.004 Ω |
| Answer» E. | |
| 68. |
The power input and output in a device are 3650 W and 3385 W with each reading in doubt by ± 10 W. The percentage uncertainty in losses is |
| A. | ± 7.55% |
| B. | ± 3.77% |
| C. | ± 11.32% |
| D. | ± 15.09% |
| Answer» B. ± 3.77% | |
| 69. |
Two resistances are R1 = 36 ± 5% and R2 = 75 ± 5%. If they are connected in parallel, the limiting error in percent will be |
| A. | 5% |
| B. | 10% |
| C. | 15% |
| D. | 20% |
| Answer» D. 20% | |
| 70. |
What would be the reading of voltmeter as shown in below figure. The voltmeter has a 0-1 V scale and is a 20000 Ω/V meter |
| A. | 0.4545 V |
| B. | 0.082 V |
| C. | 0.82 V |
| D. | 4.54 V |
| Answer» C. 0.82 V | |
| 71. |
Two resistances are : R1 = 36 Ω ± 1.89 Ω and R2 = 75 Ω ± 3.75 Ω. The sum R1 + R2 along with limiting error is |
| A. | 111 Ω ± 1.8 Ω |
| B. | 111 Ω ± 3.75 Ω |
| C. | 111 Ω ± 5.55 Ω |
| D. | 111 Ω ± 1.95 Ω |
| Answer» D. 111 Ω ± 1.95 Ω | |
| 72. |
Four capacitors are in parallel. Their values are 36.3 μF, 3.85 μF, 34.002 μF and 850 μF with an uncertainty of digit in the last place. The total capacitance in significant figures is |
| A. | 75.0 μF |
| B. | 75.0 ± 0.1 μF |
| C. | 75.1 ± 0.1 μF |
| D. | 75.002 ± 0.1 μF |
| Answer» C. 75.1 ± 0.1 μF | |
| 73. |
If A = 131 ± 4 and B = 106 ± 4, the percentage range of doubt in A - B is |
| A. | 4% |
| B. | 8% |
| C. | 16% |
| D. | 32% |
| Answer» E. | |
| 74. |
If A = 629 ± 8 and B = 131 ± 3, A - B with range of doubt is |
| A. | 498 ± 8 |
| B. | 498 ± 4 |
| C. | 498 ± 11 |
| D. | 498 ± 13 |
| Answer» D. 498 ± 13 | |
| 75. |
Two numbers are 131 ± 5 and 629 ± 3. The sum of the numbers with range of doubt is |
| A. | 760 ± 8 |
| B. | 760 ± 2 |
| C. | 760 + 8 |
| D. | 760 - 8 |
| Answer» B. 760 ± 2 | |
| 76. |
A current of 3.25 A is flowing through a resistance of 34.98 Ω. The voltage drop across resistance to the appropriate number of significant figures is |
| A. | 113.685 V |
| B. | 113.68 V |
| C. | 113.6 V |
| D. | 114 V |
| Answer» E. | |
| 77. |
Two resistances R1 = 18.7 Ω. and R2 = 3.624 Ω in series. The total resistance to the appropriate number of significant figures is |
| A. | 22.324 Ω |
| B. | 22.32 Ω |
| C. | 22.3 Ω |
| D. | 22 Ω |
| Answer» D. 22 Ω | |
| 78. |
A current of 3.18 A is flowing through resistance of 35.68 Ω. The voltage drop across resistance to the appropriate number of significant figures is |
| A. | 113.4624 V |
| B. | 113.462 V |
| C. | 113.46 V |
| D. | 113 V |
| Answer» E. | |
| 79. |
The current passing through a resistance of 100 ± 0.2% Ω is 2 ± 0.5% A. The limiting error in computation of power will be |
| A. | ± 0.7% |
| B. | ± 0.9% |
| C. | ± 1.2% |
| D. | ± 0.3% |
| Answer» D. ± 0.3% | |
| 80. |
If σ is standard deviation, variation is |
| A. | σ - 1 |
| B. | σ1.5 |
| C. | σ2 |
| D. | σ3 |
| Answer» D. σ3 | |
| 81. |
If d1, d2, ..., dn are n individual deviations, the standard deviation is |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | none of the above |
| Answer» B. [B]. | |
| 82. |
If n measurements of a quantity are made, the arithmetic mean is |
| A. | [A]. |
| B. | [B]. |
| C. | [C]. |
| D. | none of the above |
| Answer» C. [C]. | |
| 83. |
If σ standard deviation, probable error |
| A. | σ |
| B. | ± 1.19 σ |
| C. | ± 0.6745 σ |
| D. | ± 0.4125 σ |
| Answer» D. ± 0.4125 σ | |
| 84. |
A vibration galvanometer is a |
| A. | dynamometer instrument |
| B. | induction instrument |
| Answer» B. induction instrument | |
| 85. |
Which instrument needs creep compensation? |
| A. | Dynamometer wattmeter |
| B. | Induction wattmeter |
| C. | Energy meter |
| D. | Both (b) and (c) |
| Answer» D. Both (b) and (c) | |
| 86. |
The term 'Poisson's ratio' is connected with |
| A. | Bourden tube |
| B. | capacitance transducer |
| Answer» B. capacitance transducer | |
| 87. |
The resistance of a dc galvanometer is 20 Ω. A current of 10 mA causes full scale deflection. To convert it into 0-300 V voltmeter, we have to use a series resistance of |
| A. | 30000 Ω |
| B. | 29980 Ω |
| C. | 6000 Ω |
| D. | 15 Ω |
| Answer» C. 6000 Œ© | |
| 88. |
RTD is generally suitable for temperature up to |
| A. | about 800°C |
| B. | about 1500°C |
| C. | about 200°C |
| D. | about 50°C |
| Answer» B. about 1500¬∞C | |
| 89. |
When a capacitor is connected to the terminals of an ohmmeter, the pointer indicated a low resistance initially and finally come to infinity position. This shows that capacitor is |
| A. | short circuited |
| B. | all right |
| C. | faulty |
| D. | open circuited |
| Answer» C. faulty | |
| 90. |
In a moving iron voltmeter the coil has a resistance of 20 Ω and an inductance of 0.3 H. The swamping resistance in 2000 Ω. To ensure correct reading with dc as well as 50 Hz ac, the value of capacitor to be connected in parallel with swamping resistance should be |
| A. | 0.0521 μF |
| B. | 0.0622 μF |
| Answer» C. | |
| 91. |
In an induction wattmeter, the shading bands are made of non conducting material. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 92. |
Schering bridge is used to measure |
| A. | resistance |
| B. | mutual inductance |
| Answer» B. mutual inductance | |
| 93. |
The chemical effect of current is used in |
| A. | dc ampere hour meter |
| B. | dc ammeter |
| C. | ac energy meter |
| D. | all of the above |
| Answer» B. dc ammeter | |
| 94. |
In the wheatstone bridge in figure, each resistance is increased by 0.05%. The value of v0 will be |
| A. | 50 mV |
| B. | 5 mV |
| C. | 0.1 mV |
| D. | zero |
| Answer» E. | |
| 95. |
Assertion (A): A dc potentiometer measures the true open circuit emf of a source.Reason (R): At balance point, a dc potentiometer does not draw any current from the source. |
| A. | A is true R is false |
| B. | A is false R is true |
| Answer» B. A is false R is true | |
| 96. |
In low power factor wattmeter, the compensating coil is connected |
| A. | in series with current coil |
| B. | in parallel with current coil |
| C. | in series with pressure coil |
| D. | in parallel with pressure coil |
| Answer» D. in parallel with pressure coil | |
| 97. |
In a thermocouple two metal junctions between metals M1 and M2 are kept at temperature T1 and T2. The thermocouple emf is produced because |
| A. | M1, M2 are similar and T1, T2 are equal |
| B. | M1, M2 are similar but T1, T2 are unequal |
| C. | M1, M2 are dissimilar but T1, T2 are equal |
| D. | M1, M2 are dissimilar but T1, T2 are unequal |
| Answer» E. | |
| 98. |
Consider the following statements regarding electromagnetic flowmeter AC excitation is used to avoid polarisation of fluid.The meter calibration is changed as viscosity of fluid changes.Stainless steel pipes can be used for measuring the flow of liquid of high conductivity. Of the above statements |
| A. | 1, 2, 3 are correct |
| B. | 1 and 2 are correct |
| C. | 2 and 3 are correct |
| D. | 1 and 3 are correct |
| Answer» E. | |
| 99. |
In a megger the moving coil meter has a permanent magnet. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 100. |
Magnetic field intensity has the dimensions |
| A. | IL |
| B. | I2L |
| C. | IL-1 |
| D. | IL-2 |
| Answer» D. IL-2 | |