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.
| 401. |
Consider the following galvanometers D'ArsonvalBallisticVibration Which of these are permanent magnet moving coil instruments? |
| A. | 1 and 2 only |
| B. | 1, 2 and 3 |
| C. | 2 and 3 only |
| D. | 1 and 3 only |
| Answer» C. 2 and 3 only | |
| 402. |
The loss of charge method can be used to measure |
| A. | resistance of shunt |
| B. | insulation resistance of cable |
| C. | resistance of shunt winding |
| D. | both (b) and (c) |
| Answer» C. resistance of shunt winding | |
| 403. |
In figure the output V0 is |
| A. | 2V1 + V2 - 2V3 |
| B. | 2(V1 + V2) - V3 |
| C. | V1 + V2 + V3 |
| D. | V1 + 2V2 - V3 |
| Answer» B. 2(V1 + V2) - V3 | |
| 404. |
If low pressure of 10-6 mm of Hg is required to be measured, we should use |
| A. | compound pressure gauge |
| B. | thermocouple vacuum gauge |
| C. | Pirani gauge |
| D. | ionization type vacuum gauge |
| Answer» D. ionization type vacuum gauge | |
| 405. |
A meter has a square law scale. For 2 A current the deflection in 90°. For a deflection of 45°, the current is |
| A. | 0.041666666666667 |
| B. | 1.5 A |
| C. | 1.414 A |
| D. | 1.61 A |
| Answer» D. 1.61 A | |
| 406. |
Without a spectrum analyser, it is not possible to determine |
| A. | carrier frequency |
| B. | antenna pattern |
| C. | pulse width |
| D. | spurious signal strength and its location |
| Answer» B. antenna pattern | |
| 407. |
LVDT is used to measure |
| A. | displacement |
| B. | pressure |
| C. | temperature |
| D. | any of the above |
| Answer» B. pressure | |
| 408. |
The use of thermocouple meters for ac measurement leads to a scale which is |
| A. | linear |
| B. | square law |
| C. | logarithmic |
| D. | exponential |
| Answer» C. logarithmic | |
| 409. |
Assertion (A): De sauty's bridge is suitable only for pure capacitor.Reason (R): Capacitors are mostly perfect. |
| 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 | |
| 410. |
Assertion (A): The speed of a shaft can be measured by using a dc tacho generator.Reason (R): A two phase servometer can also be used as a speed transducer. |
| 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 | |
| 411. |
The emf of a Weston cell is 1.286 V. |
| A. | 1 |
| B. | |
| C. | one voltmeter, one ammeter |
| D. | two ammeters |
| Answer» C. one voltmeter, one ammeter | |
| 412. |
The advantage of LVDT over inductive bridge type transducer is that |
| A. | it gives high output for small changes in core position |
| B. | it can be used over a temperature range of - 265°C to 600°C |
| C. | it can measure displacement of moving object |
| D. | the error due to stray magnetic field is less |
| Answer» B. it can be used over a temperature range of - 265¬∞C to 600¬∞C | |
| 413. |
In a single phase power factor meter the phase difference between currents in the two pressure coils is |
| A. | exactly 0° |
| B. | approximate 0° |
| C. | exactly 90° |
| D. | approximate 90° |
| Answer» D. approximate 90¬∞ | |
| 414. |
In figure the bridge is balanced when Z4 is |
| A. | 120∠70° |
| B. | 187.5∠ - 10° |
| C. | 187.5∠ - 70° |
| D. | 333.3∠ - 70° |
| Answer» D. 333.3‚à† - 70¬∞ | |
| 415. |
A voltmeter using thermocouples measures |
| A. | rms value |
| B. | peak value |
| C. | average value |
| D. | peak to peak value |
| Answer» B. peak value | |
| 416. |
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% | |
| 417. |
The material used in RTD is |
| A. | linear |
| B. | aluminium |
| C. | silver |
| D. | platinum |
| Answer» E. | |
| 418. |
A meter having 0-1000 μA range and 1000 Ω resistance is required to be changed to 0-100 mA meter. The value of shunt resistance is about |
| A. | 1 Ω |
| B. | 10 Ω |
| C. | 99 Ω |
| D. | 100 Ω |
| Answer» C. 99 Œ© | |
| 419. |
Assertion (A): A hot wire ammeter has a cramped scale.Reason (R): The heat is proportional to square of current. |
| 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 | |
| 420. |
A dynamometer wattmeter is connected in ac circuit. The reading will be |
| A. | V-A product |
| B. | average power |
| C. | peak power |
| D. | instantaneous power |
| Answer» C. peak power | |
| 421. |
A Q meter uses the principle of |
| A. | variation of self inductance |
| B. | variation of mutual inductance |
| C. | series resonance |
| D. | none of the above |
| Answer» D. none of the above | |
| 422. |
A standard cell of 1.0185 V is used with a slide wire potentiometer. The balance was obtained at 60 cm. When an unknown emf was connected, the balance was obtained at 82 cm. The magnitude of unknown emf is |
| A. | 1.39 V |
| B. | 0.75 V |
| C. | 13.9 V |
| D. | 7.45 V |
| Answer» B. 0.75 V | |
| 423. |
Pirani gauge is used to measure |
| A. | very low pressure |
| B. | high pressure |
| C. | pressure in the range of 1 atmosphere |
| D. | fluid flow |
| Answer» B. high pressure | |
| 424. |
Thermistors are made of |
| A. | pure metals |
| B. | pure insulators |
| C. | tintered mixture of metallic oxides |
| D. | pure semiconductors |
| Answer» D. pure semiconductors | |
| 425. |
Assertion (A): Shunt of an ammeter has a low resistance.Reason (R): Shunt may be connected in series or in parallel with ammeter. |
| 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 | |
| 426. |
An amplifier has to amplify pulses of 1 H-s duration. The minimum bandwidth of amplifier must be |
| A. | 10 kHz |
| B. | 10 MHz |
| C. | 1 kHz |
| D. | 1 MHz |
| Answer» E. | |
| 427. |
Assertion (A): The scale a PMMC ammeter is linear.Reason (R): The deflecting torque of PMMC is proportional to current in the coil. |
| 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 | |
| 428. |
In which of the transformer is the secondary nearly short circuited under normal operating conditions? |
| A. | CT |
| B. | PT |
| C. | Distribution transformer |
| D. | Power transformer |
| Answer» B. PT | |
| 429. |
The scale of a dynamometer is linear when used as |
| A. | ammeter |
| B. | voltmeter |
| C. | wattmeter |
| D. | both (a) and (c) |
| Answer» D. both (a) and (c) | |
| 430. |
Heating effect of current is used in |
| A. | ammeters |
| B. | voltmeters |
| C. | both ammeters and voltmeters |
| D. | wattmeters |
| Answer» D. wattmeters | |
| 431. |
LVDT is a |
| A. | pressure transducer |
| B. | displacement transducer |
| C. | velocity transducer |
| D. | acceleration transducer |
| Answer» C. velocity transducer | |
| 432. |
Magnetic flux can be measured by |
| A. | capacitive pick up |
| B. | inductive pick up |
| C. | resistive pick up |
| D. | hall effect pick up |
| Answer» E. | |
| 433. |
In a strain measuring device using a strain gauge, the output quantity is |
| A. | voltage |
| B. | resistance |
| C. | impedance |
| D. | either (a) or (b) |
| Answer» B. resistance | |
| 434. |
The pressure coil of a wattmeter should be connected to the supply side of the current coil when |
| A. | load impedance in high |
| B. | load impedance is low |
| C. | voltage is high |
| D. | voltage is low |
| Answer» B. load impedance is low | |
| 435. |
Assertion (A): When a wattmeter is used for low impedance loads, the pressure coil is connected across the load.Reason (R): A wattmeter measures apparent power. |
| 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 | |
| 436. |
Which of these instruments is dynamometers type? |
| A. | Wattmeter |
| B. | Power factor meter |
| C. | Frequency meter |
| D. | Both (a) and (b) |
| Answer» E. | |
| 437. |
The accuracy of measurement using CRO is about |
| A. | ± 0.5% |
| B. | ± 0.05 % |
| C. | ± 1% |
| D. | ± 3% |
| Answer» E. | |
| 438. |
A voltage of about 200 V dc can be measured |
| A. | directly by dc potentiometer |
| B. | by dc potentiometer in conjunction with a volt ratio box |
| C. | a dc potentiometer in conjunction with a known resistance |
| D. | both (b) and (c) |
| Answer» C. a dc potentiometer in conjunction with a known resistance | |
| 439. |
The scale of thermocouple instrument is linear. |
| A. | 1 |
| B. | |
| C. | Iron-constantan |
| D. | Chromel-aluminium |
| Answer» C. Iron-constantan | |
| 440. |
Gauge factor of a strain gauge is |
| A. | unit change in resistance per unit change in length |
| B. | change in resistance per unit change in length |
| C. | unit change in length per unit change in resistance |
| D. | none of the above |
| Answer» B. change in resistance per unit change in length | |
| 441. |
Consider the following operation in respect of Wheatstone bridge (Kb, denotes battery key, Kg denotes galvanometer key) open Kbclose Kgclose Kbopen Kg The correct sequence of operations is |
| A. | 1, 2, 3, 4 |
| B. | 3, 1, 2, 4 |
| C. | 4, 3, 2, 1 |
| D. | 3, 2, 4, 1 |
| Answer» E. | |
| 442. |
Which of the following is not correct? |
| A. | Voltmeter should have a very high resistance |
| B. | An ammeter should have a very low resistance |
| C. | A shunt should have a very low resistance |
| D. | An electronic voltmeter draws appreciable current from source |
| Answer» E. | |
| 443. |
Which of the following statement is correct for two wattmeters method of power measurement in 3 phase circuit? |
| A. | Power can be measured by this method only for star connected loads |
| B. | When two wattmeters have equal readings power factor is 0.5. |
| C. | When power factor is 1, one of the wattmeters readings is zero |
| D. | When the two wattmeter read equal and opposite, p.f. is zero. |
| Answer» E. | |
| 444. |
A megger has a hand driven dc generator. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 445. |
The coils of Drysdale polar potentiometer are wound non-inductively. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 446. |
A moving iron instrument gives correct reading when used at |
| A. | low frequencies |
| B. | high frequencies |
| C. | only one frequency |
| D. | all frequencies upto a certain value |
| Answer» D. all frequencies upto a certain value | |
| 447. |
Hay's bridge is suitable for inductances having low L/R ratio. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» C. 1 | |
| 448. |
A digital voltmeter has a read out range from 0 to 999 counts. If the full scale reading is 9.999 V, the resolution is |
| A. | 1 V |
| B. | 0.01 V |
| C. | 1 mV |
| D. | 1 μV |
| Answer» D. 1 ŒºV | |
| 449. |
Two wattmeter method for 3 phase power measurement can be used only for |
| A. | balanced loads |
| B. | unbalanced loads |
| C. | both balanced and unbalanced loads |
| D. | star connected loads |
| Answer» D. star connected loads | |
| 450. |
Insertion of a dielectric material between the plates of an air capacitor |
| A. | increases the capacitance |
| B. | decreases capacitance |
| C. | has no effect an capacitance |
| D. | increases breakdown voltage |
| Answer» B. decreases capacitance | |