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.
| 301. |
Which of the following instruments is used almost exclusively to measure radio frequency currents? |
| A. | Moving coil |
| B. | Rectifier |
| C. | Moving iron |
| D. | Thermocouple |
| Answer» E. | |
| 302. |
The effect of lead resistance is important in measurement of |
| A. | resistance of shunt |
| B. | resistance of shunt winding |
| C. | resistance of ammeter |
| D. | both (a) and (c) |
| Answer» E. | |
| 303. |
In a digital measuring device the input electrical signal is in the frequency range of dc to ac (50) Hz. It must be sampled at a rate of |
| A. | f times/sec |
| B. | 0.5 f times/sec |
| C. | 0.25 f times/sec |
| D. | 2 f times/sec |
| Answer» E. | |
| 304. |
In semiconductor strain gauge |
| A. | resistance increases with strain |
| B. | resistance decreases with strain |
| C. | resistance increases with strain in p type and decreases with strain in n type |
| D. | resistance increases with strain in n type and decreases with strain in p type |
| Answer» D. resistance increases with strain in n type and decreases with strain in p type | |
| 305. |
Consider the following instruments Tangent galvanometerRayleigh current balanceHousehold energy meterHot wire ammeter Out of above absolute instruments are |
| A. | 1, 2 and 3 |
| B. | 1, 2 and 4 |
| C. | 1 and 2 |
| D. | 2, 3 and 4 |
| Answer» D. 2, 3 and 4 | |
| 306. |
The instrument used to check insulation of household wiring is |
| A. | megger |
| B. | ohmmeter |
| C. | multimeter |
| D. | high resistance voltmeter |
| Answer» B. ohmmeter | |
| 307. |
Assertion (A): A transducer needs an output measuring or display device for measuring a non electrical quantity.Reason (R): In some transducers the output voltage is too small and needs amplification before it can be measured. |
| 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 | |
| 308. |
The dimensions of force are |
| A. | MLT-2 |
| B. | ML-1T-2 |
| C. | MLT-1 |
| D. | ML2T-2 |
| Answer» B. ML-1T-2 | |
| 309. |
The deflection sensitivity of a CRO is generally expressed in |
| A. | meter/V |
| B. | cm/V |
| C. | V/meter |
| D. | V/cm |
| Answer» B. cm/V | |
| 310. |
A linear displacement digital transducer generally uses |
| A. | straight binary code |
| B. | BCD |
| C. | gray code |
| D. | hexadecimal code |
| Answer» D. hexadecimal code | |
| 311. |
With a variable reluctance tachometer having 60 rotor teeth the count reads 3600 counts per minute. The speed in RPM is |
| A. | 36 |
| B. | 60 |
| C. | 360 |
| D. | 3600 |
| Answer» C. 360 | |
| 312. |
In a low power factor wattmeter, compensation for pressure coil current is provided. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 313. |
Assertion (A): In a CRT, grid is kept at negative potential with respect to cathode.Reason (R): The function of grid in an electronic tube is to control the number of electrons. |
| 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 | |
| 314. |
The increase in intensity of trace in a CRO causes a change in |
| A. | beam current |
| B. | frequency of time base |
| C. | gain of Y amplifier |
| D. | accelerating voltage |
| Answer» B. frequency of time base | |
| 315. |
A permanent magnet moving coil meter can be used as |
| A. | ac only |
| B. | dc only |
| C. | both ac and dc |
| D. | low frequency ac and dc |
| Answer» E. | |
| 316. |
It is required to study transients during switching process. Which CRO should be preferred? |
| A. | Ordinary CRO |
| B. | Dual beam CRO |
| C. | Dual trace CRO |
| D. | Storage oscilloscope |
| Answer» E. | |
| 317. |
A multimeter can be used as ohmmeter. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 318. |
An average responding voltmeter using full wave rectifier has been calibrated to read 1 V for 1 V rms sinusoidal input. For 1 V peak to peak square wave input, the meter reading will be |
| A. | |
| B. | zero V |
| Answer» B. zero V | |
| 319. |
Assertion (A): Energy meters use induction principle.Reason (R): Induction wattmeter is less accurate than a dynamometer wattmeter. |
| 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 | |
| 320. |
The response of a thermistor overs the whole of its temperatures range is |
| A. | linear |
| B. | non-linear |
| C. | almost linear |
| D. | either (a) or (c) |
| Answer» C. almost linear | |
| 321. |
A 300 V voltmeter has an accuracy of ± 2% of full scale deflection. When the reading is 222 V, the actual voltage |
| A. | lies between 217.56 and 226.44 V |
| B. | lies between 217.4 and 226.6 V |
| C. | lies between 216 and 228 V |
| D. | is exact 222 V |
| Answer» D. is exact 222 V | |
| 322. |
The advantage of semiconductor strain gauge over resistance strain gauge is |
| A. | it is more sensitve |
| B. | it is more linear |
| C. | it is less temperature dependent |
| D. | it is cheaper |
| Answer» B. it is more linear | |
| 323. |
Which of the following can be used for measuring capacitance? |
| A. | De sauty bridge |
| B. | Maxwell's bridge |
| C. | Anderson bridge |
| D. | Hay's bridge |
| Answer» B. Maxwell's bridge | |
| 324. |
During testing of an energy meter, the energy recorded by meter was 0.05 kWh and correct energy was found to be 0.09 kWh. The error and correction respectively are |
| A. | -0.01 kWh and 0.01 kWh |
| B. | 0.01 kWh and -0.01 kWh |
| C. | -0.01 kWh and ± 0.01 kWh |
| D. | ± 0.01 kWh and 0.01 kWh |
| Answer» B. 0.01 kWh and -0.01 kWh | |
| 325. |
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 | |
| 326. |
A 0-200 V voltmeter has a sensitivity of 1 kΩ per volt. The resistance of voltmeter is |
| A. | 1 kΩ |
| B. | 200 kΩ |
| C. | 100 kΩ |
| D. | 50 kΩ |
| Answer» C. 100 kŒ© | |
| 327. |
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. | 43586 |
| D. | 43617 |
| Answer» B. 5 | |
| 328. |
Consider the following statements regarding electro-dynamometer type indicating instrument It can be used for measuring Direct currentAlternating currentDirect voltageAlternating voltage Of these statements |
| A. | 1 and 2 are corect |
| B. | 3 and 4 are correct |
| C. | 1 and 3 are correct |
| D. | 1, 2, 3, 4 are correct |
| Answer» E. | |
| 329. |
Use of high permeability core in moving iron instrument helps in |
| A. | reducing size of meter |
| B. | increasing sensitivity |
| C. | reducing temperature error |
| D. | all of the above |
| Answer» C. reducing temperature error | |
| 330. |
In a vibrating reed frequency meter the natural frequency of two adjacent reeds have a difference of |
| A. | 0.25 Hz |
| B. | 0.5 Hz |
| C. | 1.25 Hz |
| D. | 1 Hz |
| Answer» C. 1.25 Hz | |
| 331. |
Current density has the dimensions |
| A. | IL |
| B. | IL-2 |
| C. | IL-3 |
| D. | I2L-2 |
| Answer» C. IL-3 | |
| 332. |
The braking torque in single phase energy meter is proportional to speed of disc. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 333. |
The precision of an instrument indicates its ability to reproduce a certain reading with a given |
| A. | drift |
| B. | resolutions |
| C. | shift |
| D. | consistency |
| Answer» E. | |
| 334. |
In a dynamometer instrument, the moving coil is pressure coil. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 335. |
A Maxwell's bridge has the unknown inductance in one arm and resistance in the other three arms. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 336. |
A moving coil meter has a resistance of 50 ohms and a full scale deflection current of 20 mA. To convert it into a voltmeter of 0-100 V range, the series resistance should be |
| A. | 5000 Ω |
| B. | 5050 Ω |
| C. | 4950 Ω |
| D. | 505 Ω |
| Answer» D. 505 Œ© | |
| 337. |
Which of the following is active transducer? |
| A. | Photoelectric |
| B. | Photovoltaic |
| C. | Photoconductive |
| D. | Photoemissive |
| Answer» C. Photoconductive | |
| 338. |
If two time varying signals of equal magnitude and zero phase displacement are applied to X and Y plates respectively; of CRO, the display will be |
| A. | a straight line |
| B. | a circle |
| C. | an ellipse |
| D. | a square |
| Answer» B. a circle | |
| 339. |
Wheatstone bridge is suitable for low resistances. |
| A. | 1 |
| B. | |
| Answer» C. | |
| 340. |
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 | |
| 341. |
Assertion (A): A universal RLC bridge has a battery and also a high frequency ac source.Reason (R): RLC bridge uses a Wienbridge arrangement for measuring capacitance. |
| 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 | |
| 342. |
A resistance strain gauge is usually |
| A. | wire grid type |
| B. | foil type |
| C. | any of these |
| D. | none of these |
| Answer» D. none of these | |
| 343. |
In a Weston synchronoscope the deflecting torque is zero when |
| A. | currents in fixed and moving coils are in phase |
| B. | currents in fixed and moving coils are out of phase by 90° |
| C. | currents in fixed and moving coils are out of phase by 60° |
| D. | none of the above |
| Answer» C. currents in fixed and moving coils are out of phase by 60¬∞ | |
| 344. |
It is required that a strain gauge has gauge factor of 100. The proper strain gauge is |
| A. | constantan strain gauge |
| B. | nichrome strain gauge |
| C. | semiconductor strain gauge |
| D. | alloy strain gauge |
| Answer» D. alloy strain gauge | |
| 345. |
If σ is standard deviation, variation is |
| A. | σ - 1 |
| B. | σ1.5 |
| C. | σ2 |
| D. | σ3 |
| Answer» D. œÉ3 | |
| 346. |
A wire strain gauge has a gauge factor of 2, resistance of 125 Ω and length 1 m. If length of wire changes by .005 m, change in resistance will be |
| A. | 0.25 Ω |
| B. | 0.5 Ω |
| C. | 1.25 Ω |
| D. | 2.5 Ω |
| Answer» D. 2.5 Œ© | |
| 347. |
Assertion (A): Strain measurement using strain gauge invariably requires a dummy strain gauge.Reason (R): The resistance of strain gauge depends on temperature. |
| 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 | |
| 348. |
In Schering bridge, the potential of detector above earth potential is about |
| A. | a few volts |
| B. | 10 kV |
| C. | 1000 V |
| D. | either (a) or (b) |
| Answer» B. 10 kV | |
| 349. |
The total insulation resistance consists of insulation volume resistance and surface leakage resistance. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 350. |
The current through the coil of an electromagnet is doubled. The magnetic field around the coil |
| A. | is halved |
| B. | is doubled |
| C. | becomes four times |
| D. | remains the same |
| Answer» C. becomes four times | |