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.
| 201. |
Schering bridge operates at a high voltage of about 10 kV. |
| A. | 1 |
| B. | |
| C. | Moving iron ammeter |
| D. | PMMC ammeter |
| Answer» B. | |
| 202. |
Figure shows the equivalent circuit of resistor. The resistor is non-inductive when |
| A. | R = L/C |
| B. | LR = L/C |
| C. | L = CR2 |
| D. | C = LR2 |
| Answer» D. C = LR2 | |
| 203. |
The volt ratio box is basically a |
| A. | potential divider |
| B. | current transformer |
| C. | a high resistance voltmeter |
| D. | either (a) or (c) |
| Answer» B. current transformer | |
| 204. |
In a hot wire instrument, the deflection is proportional to |
| A. | rms value of ac current |
| B. | either (a) or (b) |
| C. | ac only |
| D. | dc only |
| Answer» B. either (a) or (b) | |
| 205. |
Which one of the following effects is used in measuring power? |
| A. | Seeback |
| B. | Ferrari |
| C. | Induction |
| D. | Hall |
| Answer» D. Hall | |
| 206. |
Which of the following quantities have same dimension in emu and esu? CurrentElectrical powerElectrical energy Select the answer as per following codes |
| A. | 1 only |
| B. | 1 and 2 |
| C. | 2 and 3 |
| D. | 1 and 3 |
| Answer» D. 1 and 3 | |
| 207. |
A digital voltmeter has a 4 1/2 digit display. The 1 V range can measure voltage up to |
| A. | 0.9999 V |
| B. | 1.9999 V |
| C. | 0.199 V |
| D. | 9.999 V |
| Answer» D. 9.999 V | |
| 208. |
The gauge factor of a semiconductor strain gauge is about |
| A. | 2 |
| B. | 10 |
| C. | 100 |
| D. | 1000 |
| Answer» D. 1000 | |
| 209. |
To measure a resistance of about 8 ohms we should use |
| A. | Meggar |
| B. | Either (b) or (c) |
| C. | optical pyrometer |
| D. | thermistor based thermometer |
| Answer» C. optical pyrometer | |
| 210. |
Consider the following statements about a moving iron instrument It is an unpolarised instrument.It has permanent magnet.It has a fixed coil.It has two iron vanes. Of these statements |
| A. | 1, 2, 3 are correct |
| B. | 1, 2, 4 are correct |
| C. | 1, 3 and 4 are correct |
| D. | 2, 3, 4 are correct |
| Answer» D. 2, 3, 4 are correct | |
| 211. |
A moving coil meter has 10 Ω resistance and requires 40 mA for full scale deflection. The shunt resistance required to convert it into 0-2 A ammeter is |
| A. | 0.1021 Ω |
| B. | 0.2041 Ω |
| C. | 0.256 Ω |
| D. | 0.4210 Ω |
| Answer» C. 0.256 Œ© | |
| 212. |
Which of these has poor overload capacity? |
| A. | PMMC instrument |
| B. | Hot wire instrument |
| C. | Dynamometer instrument |
| D. | Both (a) and (c) |
| Answer» C. Dynamometer instrument | |
| 213. |
A power factor meter has |
| A. | two current circuits and two pressure circuits |
| B. | two current circuits and one pressure circuit |
| C. | copper wire |
| D. | gold wire |
| Answer» C. copper wire | |
| 214. |
The dynamometer principle can be used for |
| A. | ammeter only |
| B. | voltmeter only |
| C. | wattmeter only |
| D. | ammeter, voltmeter and wattmeter |
| Answer» E. | |
| 215. |
Bridge circuits using RTD in temperature measurement usually employ 3 lead system so as to obtain |
| A. | higher sensitivity |
| B. | better impedance matching |
| C. | compensation for signal wire resistance |
| D. | reduction in power consumption |
| Answer» D. reduction in power consumption | |
| 216. |
In portable instruments, damping is provided by |
| A. | spring |
| B. | gravity |
| C. | eddy current |
| D. | either (a) or (c) |
| Answer» B. gravity | |
| 217. |
Shaft encoder is used to measure |
| A. | angular position |
| B. | linear position |
| C. | linear velocity |
| D. | linear acceleration |
| Answer» B. linear position | |
| 218. |
Assertion (A): Damping in a vibration galvanometer is small.Reason (R): Vibration galvanometer is a PMMC instrument. |
| 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 | |
| 219. |
A phase shifting transformer is used in conjunction with |
| A. | DC slide wire potentiometer |
| B. | Crompton potentiometer |
| C. | AC coordinate potentiometer |
| D. | Drysdale potentiometer |
| Answer» E. | |
| 220. |
In most of instruments, the controlling torque is provided by |
| A. | fluid fraction |
| B. | spring |
| C. | eddy current |
| D. | either (a) or (c) |
| Answer» D. either (a) or (c) | |
| 221. |
In measurements using CRO, Lissajous patterns are used to |
| A. | measure magnitude of peak voltage |
| B. | measure frequency |
| C. | measure impedance |
| D. | measure current |
| Answer» C. measure impedance | |
| 222. |
An induction wattmeter can be used for |
| A. | dc only |
| B. | 50 Hz ac only |
| C. | both ac and dc |
| D. | high frequency ac only |
| Answer» C. both ac and dc | |
| 223. |
Assertion (A): Electrodynamic instrument is not used as ammeter or voltmeter.Reason (R): Electrodynamic instrument is more costly than PMMC and moving iron instrument. |
| 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 | |
| 224. |
The electrical power to a megger is provided by |
| A. | battery |
| B. | inverter |
| C. | permanent magnet dc generator |
| D. | ac generator |
| Answer» D. ac generator | |
| 225. |
The sensitivity of a potentiometer can be increased by |
| A. | increasing the length of wire |
| B. | decreasing the length of wire |
| C. | increasing the current in the wire |
| D. | decreasing the current in the wire |
| Answer» B. decreasing the length of wire | |
| 226. |
If the secondary burden of a CT 15 VA and secondary current is 5 A, the load impedance of CT is |
| A. | 0.6 Ω |
| B. | 5 Ω |
| C. | 6 Ω |
| D. | 10 Ω |
| Answer» B. 5 Œ© | |
| 227. |
Piezoelectric effect can be used to measure |
| A. | force |
| B. | strain |
| C. | acceleration |
| D. | all of the above |
| Answer» E. | |
| 228. |
To measure dielectric loss you would use |
| A. | Anderson bridge |
| B. | Kelvin bridge |
| C. | Schering bridge |
| D. | Maxwell's bridge |
| Answer» D. Maxwell's bridge | |
| 229. |
Which of the following instruments has non-linear scale? Moving coil instrumentMoving iron instrumentElectrostatic instrumentRectifier instrument Select the answer as per following codes |
| A. | 2 only |
| B. | 2 and 3 only |
| C. | 2, 3 and 1 |
| D. | 1, 2, 3 and 4 |
| Answer» C. 2, 3 and 1 | |
| 230. |
A moving coil meter has a shunt of 0.02 Ω resistance. If coil resistance is 1000 Ω and a potential difference of 500 mV is required across it to cause full scale deflection, the current through shunt is |
| A. | 2.5 A |
| B. | 25 A |
| C. | 0.25 A |
| D. | 0.025 A |
| Answer» C. 0.25 A | |
| 231. |
In measurements using strain gauge, the dummy strain gauge is used to |
| A. | compensate for resistance of strain gauge |
| B. | compensate for change in temperature |
| C. | compensate for error due to change in voltage of battery |
| D. | compensate for error in voltmeter |
| Answer» C. compensate for error due to change in voltage of battery | |
| 232. |
The dimensions of EMF are |
| A. | ML2I-1T-3 |
| B. | M-1T-3 |
| C. | ML2I-2T-3 |
| D. | ML3I-1T-3 |
| Answer» B. M-1T-3 | |
| 233. |
The time base generator in a CRO gives an output which is |
| A. | low frequency sinusoidal |
| B. | high frequency sinusoidal |
| C. | low frequency rectangular |
| D. | high frequency sawtooth |
| Answer» E. | |
| 234. |
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 kŒ© | |
| 235. |
A capacitance transducer has two plates each of area 5 mm2. The coil gap is 2 mm. Displacement sensitivity due to change in gap length is |
| A. | 11.1 pF/cm |
| B. | 44.2 pF/cm |
| C. | 52.3 pF/cm |
| D. | 66.3 pF/cm |
| Answer» B. 44.2 pF/cm | |
| 236. |
In a low power factor wattmeter, the resistance of pressure coil is more than in ordinary wattmeter. |
| A. | 1 |
| B. | |
| Answer» B. | |
| 237. |
For measurement of surface temperature of solids the elements of RTD is usually in the shape of |
| A. | bar |
| B. | coil |
| C. | flat grid |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 238. |
Which of the following does not use the principle of change in inductance? |
| A. | LVDT |
| B. | Inductance displacement transducer |
| C. | Strain gauge |
| D. | Reluctance pick up |
| Answer» D. Reluctance pick up | |
| 239. |
The function of shunt in an ammeter is to |
| A. | by pass the current |
| B. | increase sensitivity of meter |
| C. | increase resistance of meter |
| D. | all of the above |
| Answer» B. increase sensitivity of meter | |
| 240. |
Which of the following closely represents the resistance-temperature characteristics of thermistor? |
| A. | RT = a R0 eb/t |
| B. | RT = a R0 E-b/t |
| C. | RT = - a R0 e-b/t |
| D. | RT = - R0 eb/t |
| Answer» B. RT = a R0 E-b/t | |
| 241. |
If temperature increases by about 50°, the resistance of thermistor changes to |
| A. | half of its initial value |
| B. | twice of its initial value |
| C. | eight times of its initial value |
| D. | one eight of its initial value |
| Answer» E. | |
| 242. |
The ac bridge in figure is balanced. Z1 = 100∠30°, Z2 = 150∠0°, Z3 = 250∠ - 40° Then Z4 = |
| A. | 375∠70° Ω |
| B. | 375∠ - 70° Ω |
| C. | 150∠0° Ω |
| D. | 150∠20° Ω |
| Answer» C. 150‚à†0¬∞ Œ© | |
| 243. |
An instrument of accuracy class 1 can have an error equal to |
| A. | + 1% of reading |
| B. | ± 1% of reading |
| C. | ± 1% of full scale deflection |
| D. | + 1% of full scale deflection |
| Answer» D. + 1% of full scale deflection | |
| 244. |
Which of these has a magnetic brake? |
| A. | Thermocouple ammeter |
| B. | Energy meter |
| C. | Dynamometer wattmeter |
| D. | Frequency meter |
| Answer» C. Dynamometer wattmeter | |
| 245. |
A single element strain gauge bridge has two fixed resistances R1 and R1 of 120 Ω each and a variable resistance which gives full deflection at 120 Ω for zero strain and 120.6 Ω for straine e. If gauge factor is 2, strain e is |
| A. | 0.0025 |
| B. | 0.0035 |
| C. | 0.005 |
| D. | 0.0075 |
| Answer» B. 0.0035 | |
| 246. |
Assertion (A): Secondary instruments require calibration at frequent intervals.Reason (R): Secondary instruments have many errors. |
| 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 | |
| 247. |
Loading effect is primarily caused by instruments having |
| A. | high resistance |
| B. | high sensitivity |
| C. | low sensitivity |
| D. | high range |
| Answer» D. high range | |
| 248. |
In household energy meters the flux of series magnet is in phase with current but the flux of shunt magnet lags the voltage by 88°. The reading of energy meters |
| A. | will be correct |
| B. | will have a negative error |
| C. | will have a positive error |
| D. | may have positive or negative error |
| Answer» C. will have a positive error | |
| 249. |
Two ammeters having resistances of 0.5 Ω and 0.25 Ω and having full scale reading of 25 A each are connected in parallel. To ensure that neither of them goes beyond scale, the total current should not be more than |
| A. | 50 A |
| B. | 37.5 A |
| C. | 25 A |
| D. | 40 A |
| Answer» C. 25 A | |
| 250. |
Which of the following draws minimum power from source? |
| A. | PMMC |
| B. | Electronic voltmeter |
| C. | Electrostatic voltmeter |
| D. | Moving iron voltmeter |
| Answer» C. Electrostatic voltmeter | |