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.
| 501. |
The scale of hot wire instrument is linear. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 502. |
The angle δ for a mica capacitor is about |
| A. | 25° |
| B. | 15° |
| C. | 5° |
| D. | 1° |
| Answer» E. | |
| 503. |
A volt ratio box should have low resistance. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 504. |
A sinusoidal signal is measured by CRO. The scale is set at 4 mV/cm. If vertical distance between positive and negative peaks is 6 cm, the peak value of ac signal is |
| A. | 6 mV |
| B. | 12 mV |
| C. | 24 mV |
| D. | 3 mV |
| Answer» C. 24 mV | |
| 505. |
An induction wattmeter can be used for ac only. |
| A. | 1 |
| B. | |
| C. | Kelvin's double bridge |
| D. | Wheatstone bridge |
| Answer» B. | |
| 506. |
In a CRO the Y plates are oriented |
| A. | horizontally |
| B. | vertically |
| C. | at an angle of 20° of horizontal |
| D. | at an angle of 70° of horizontal |
| Answer» B. vertically | |
| 507. |
If φsh is flux of shunt magnet, φse is flux of series magnet, ish is eddy current due to φse, the torque in an induction wattmeter is proportional to |
| A. | φse ise + φsh ish |
| B. | φsh ise - φse ish |
| C. | φsh ish - φse ise |
| D. | φsh ish + φse ise |
| Answer» C. œÜsh ish - œÜse ise | |
| 508. |
Two resistances are R1 = 36 ± 5% and R2 = 75 ± 5%. If they are connected in parallel, the limiting error in percent will be |
| A. | 0.05 |
| B. | 0.1 |
| C. | 0.15 |
| D. | 0.2 |
| Answer» D. 0.2 | |
| 509. |
A piezoelectric force transducer has a charge sensitivity of 20 pC/N. It is connected to a charge amplifier and overall gain of transducer and amplifier is 50 mV/N. The gain of amplifier is |
| A. | 1 mV/pC |
| B. | 1.5 mV/pC |
| C. | 2.5 mV/pC |
| D. | 4 mV/pC |
| Answer» D. 4 mV/pC | |
| 510. |
For use at 50 Hz the range of scale of vibrating reed frequency meter is |
| A. | 25 - 75 Hz |
| B. | 40 - 60 Hz |
| C. | 47 - 53 Hz |
| D. | 42 - 58 Hz |
| Answer» D. 42 - 58 Hz | |
| 511. |
Consider the following statements Thermistor is more sensitive than platinum resistance thermometerThe resistance of thermistor is solely a function of its absolute temperature whether the source of heat is external or internalThermistor has linear temperature-resistance relationshipThermistor has linear negative temperature coefficient Of the Statements, the correct statements are |
| A. | 1 and 2 |
| B. | 3 and 4 |
| C. | 1, 2, 3, 4 |
| D. | 1, 2 and 4 |
| Answer» E. | |
| 512. |
Assertion (A): The sign and magnitude of displacement can be measured by an LVDT.Reason (R): LVDT is based on the principle of mutual inductance. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true R is false |
| D. | A is false R is true |
| Answer» C. A is true R is false | |
| 513. |
Assertion (A): Wien bridge can be used for measuring frequency.Reason (R): A frequency meter for 50 Hz system has a frequency range of 40 to 60 Hz. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true R is false |
| D. | A is false R is true |
| Answer» D. A is false R is true | |
| 514. |
The numbers of accelerating anodes in a CRO is |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» C. 3 | |
| 515. |
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 Œ© | |
| 516. |
In a phase shifting transformer the currents in the two stator winding are in phase. |
| A. | 1 |
| B. | |
| C. | one current and one pressure circuit |
| D. | one current circuit and two pressure circuits |
| Answer» C. one current and one pressure circuit | |
| 517. |
The household energy meter is |
| A. | indicating instrument |
| B. | recording instrument |
| C. | integrating instrument |
| D. | none of the above |
| Answer» D. none of the above | |
| 518. |
Assertion (A): Absolute instruments are used in standard laboratories.Reason (R): Absolute instruments do not require calibration. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true R is false |
| D. | A is false R is true |
| Answer» C. A is true R is false | |
| 519. |
The channel required for FM telemetry is |
| A. | same as required for AM telemetry |
| B. | smaller than that required by AM telemetry |
| C. | 100 times that required for AM telemetry |
| D. | 10 times that required for AM telemetry |
| Answer» D. 10 times that required for AM telemetry | |
| 520. |
A capacitance transducer can be used to measure |
| A. | thickness of sheet |
| B. | displacement |
| C. | level of fluids |
| D. | all of the above |
| Answer» E. | |
| 521. |
To measure moisture in wood, the most suitable method is |
| A. | electric conduction |
| B. | electrical-capacitive |
| C. | absorption of radiation |
| D. | equilibrium-moisture Vs humidity |
| Answer» B. electrical-capacitive | |
| 522. |
If eddy current damping is to be used, the disc of instrument should be |
| A. | non-conducting and non-magnetic |
| B. | conducting and magnetic |
| C. | conducting and non-magnetic |
| D. | non-conducting and magnetic |
| Answer» D. non-conducting and magnetic | |
| 523. |
A single phase energy meter has the rating 1200 resolutions/ kWh. If a 500 W electric gadget is used for 4 hours, the energy meter will make |
| A. | 1200 revolutions |
| B. | 1800 revolutions |
| C. | 2100 revolutions |
| D. | 2400 revolutions |
| Answer» E. | |
| 524. |
A Hall effect transducer has KH = - 1 x 10-8. If B = 1 Wb/m2, I = 3 A and bismuth slab is 2 mm wide, the Hall voltage is |
| A. | -7.5 x 10-6 V |
| B. | -15 x 10-6 |
| C. | -20 x 10-4 V |
| D. | -22.5 x 10-4 V |
| Answer» C. -20 x 10-4 V | |
| 525. |
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 Œ© | |
| 526. |
A digital voltmeter can count from 0 to 9999. If full scale reading is 9.999 V, the resolution of full scale reading is |
| A. | 0.001 |
| B. | 1000 |
| C. | 2 digit |
| D. | 1 mV |
| Answer» E. | |
| 527. |
To avoid the effect of stray magnetic fields in ac bridge we can use |
| A. | magnetic screening |
| B. | Wagner earthing device |
| C. | wave filter |
| D. | transformer |
| Answer» B. Wagner earthing device | |
| 528. |
A data signal having frequency components from dc to 50 Hz is to be sent through pulse code modulation using an 8 digit code. The minimum carrier channel bandwidth is |
| A. | 1 kHz |
| B. | 2 kHz |
| C. | 4 kHz |
| D. | 8 kHz |
| Answer» D. 8 kHz | |
| 529. |
The scale of PMMC instrument is linear. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 530. |
An oscilloscope has an input impedance consisting of 1 MΩ and 20 pF is parallel. A high impedance probe connected to input of this oscilloscope has a 10 MΩ series resistance. This 10 MΩ series resistance |
| A. | may not be shunted |
| B. | should be shunted by 2 pF capacitor |
| C. | should be shunted by 20 pF capacitor |
| D. | should be shunted by 200 pF capacitor |
| Answer» C. should be shunted by 20 pF capacitor | |
| 531. |
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 Œ© | |
| 532. |
The coil of a moving coil meter has 100 turns, is 40 mm long and 30 mm wide. The control torque is 240 x 10-6 N-m on full scale. If B = 1 Wb/m2, range of meter is |
| A. | 1 mA |
| B. | 2 mA |
| C. | 3 mA |
| D. | 4 mA |
| Answer» C. 3 mA | |
| 533. |
Figure shows an RC potentiometer to measure ac voltage. It is desired that V0/Vi should be independent of frequency. The value of C should be |
| A. | 10 μF |
| B. | 11 μF |
| C. | 0.1 μF |
| D. | 0.09 μF |
| Answer» B. 11 ŒºF | |
| 534. |
The difference between measured value and true value is called |
| A. | gross error |
| B. | relative error |
| C. | probable error |
| D. | absolute error |
| Answer» E. | |
| 535. |
A digital frequency counter can be converted to DVM by addition of a suitable |
| A. | voltage controlled oscillator |
| B. | D/A converter |
| C. | power amplifier |
| D. | operational amplifier |
| Answer» C. power amplifier | |
| 536. |
If A = 131 ± 4 and B = 106 ± 4, the percentage range of doubt in A - B is |
| A. | 0.04 |
| B. | 0.08 |
| C. | 0.16 |
| D. | 0.32 |
| Answer» E. | |
| 537. |
Crompton potentiometer has |
| A. | 14 coils and a slide wire all having the same resistance |
| B. | 14 coils and a slide wire but the resistance of slide wire is half that of each coil |
| C. | 14 coils each of different resistance |
| D. | 14 coils out of which 7 coils have resistance which is twice that of remaining 7 coils |
| Answer» B. 14 coils and a slide wire but the resistance of slide wire is half that of each coil | |
| 538. |
It is required to measure a low magnitude high frequency current. The proper instrument is |
| A. | moving iron |
| B. | dynamometer |
| C. | thermocouple |
| D. | induction |
| Answer» D. induction | |
| 539. |
A universal RLC bridge uses |
| A. | Maxwell bridge for measurement of inductance and De Sauty's bridge for measurement of capacitance |
| B. | Maxwell's bridge for measurement of inductance and modified De Sauty bridge for measurement of capacitance |
| C. | Maxwell Wien bridge for measurement of inductance and modified De Sauty bridge for measurement of inductance |
| D. | Maxwell Wien bridge for measurement of inductance and Wien bridge for measurement of capacitance |
| Answer» D. Maxwell Wien bridge for measurement of inductance and Wien bridge for measurement of capacitance | |
| 540. |
Assertion (A): When frequencies of signals fed to X and Y plates of CRO are multiples of each other, Lissajous pattern is displayed on screen.Reason (R): In a CRO, the vertical deflection is proportional to voltage applied to Y plates. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true R is false |
| D. | A is false R is true |
| Answer» C. A is true R is false | |
| 541. |
Induction wattmeter can be used in |
| A. | ac circuit only |
| B. | dc circuit only |
| C. | both ac and dc circuit |
| D. | ac 3 phase only |
| Answer» B. dc circuit only | |
| 542. |
Potentiometer method of dc voltage measurement is more accurate than direct measurement using a voltmeter because |
| A. | it loads the circuit to maximum extent |
| B. | it loads the circuit moderately |
| C. | it does not load the circuit at all |
| D. | it uses centre zero galvanometer instead of Voltmeters |
| Answer» D. it uses centre zero galvanometer instead of Voltmeters | |
| 543. |
As per BIS, the number of accuracy classes of instrument is |
| A. | 5 |
| B. | 6 |
| C. | 7 |
| D. | 8 |
| Answer» E. | |
| 544. |
Assertion (A): Double Kelvin's bridge is used to measure low resistances.Reason (R): In low resistance, the contact and lead resistances are very important. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true R is false |
| D. | A is false R is true |
| Answer» B. Both A and R are true but R is not correct explanation of A | |
| 545. |
Magnetic effect of current is used in |
| A. | ammeters |
| B. | voltmeters |
| C. | wattmeters |
| D. | ammeters, voltmeters, wattmeters and energy meters |
| Answer» E. | |
| 546. |
The operating voltage of a megger is about |
| A. | 100 V |
| B. | 12 V |
| C. | 6 V |
| D. | 1 V |
| Answer» B. 12 V | |
| 547. |
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% | |
| 548. |
Assertion (A): Hall effect is observed in all metals but is very appreciable in semiconductors.Reason (R): Hall effect transducer is very suitable for measurement of magnetic flux density. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true but R is not correct explanation of A |
| C. | A is true R is false |
| D. | A is false R is true |
| Answer» C. A is true R is false | |
| 549. |
For measuring current at a high frequency we should use |
| A. | moving iron instrument |
| B. | electrostatic instrument |
| C. | thermocouple instrument |
| D. | moving coil instrument |
| Answer» D. moving coil instrument | |
| 550. |
A single phase energy meter operates on induction principle. |
| A. | 1 |
| B. | |
| C. | ± 0.5% |
| D. | ± 0.05 % |
| Answer» B. | |