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.
| 151. |
In the balanced bridge shown in figure. X should be |
| A. | a self inductance having resistance |
| B. | a capacitance |
| C. | a non-inductive resistance |
| D. | an inductance and capacitance in parallel |
| Answer» B. a capacitance | |
| 152. |
In measuring a resistance by voltmeter-ammeter method, the voltmeter can be connected either across supply or across the resistance. If the resistance is low, the voltmeters should be connected |
| A. | across the supply |
| B. | across the resistance |
| C. | either in two positions |
| D. | preferably across the supply |
| Answer» C. either in two positions | |
| 153. |
A land line telemetry system is suitable for distance upto |
| A. | about 1 km only |
| B. | about 10 km only |
| C. | about 100 km only |
| D. | any of the above |
| Answer» B. about 10 km only | |
| 154. |
Panel type instruments are used in |
| A. | power stations |
| B. | automobiles |
| C. | industries |
| D. | all of the above |
| Answer» E. | |
| 155. |
Watthour meter is an integrating instrument |
| A. | 1 |
| B. | |
| C. | secondary instrument |
| D. | absolute instrument |
| Answer» B. | |
| 156. |
De Sauty bridge is very widely used due to |
| A. | perfect balance for air capacitors |
| B. | maximum sensitivity |
| C. | moving coils instrument |
| D. | moving iron instrument |
| Answer» B. maximum sensitivity | |
| 157. |
The dynamic characteristics of capacitive transducer are similar to those of |
| A. | notch filter |
| B. | band stop filter |
| C. | battery |
| D. | inverter |
| Answer» C. battery | |
| 158. |
A 24 mm long conductor has a resistance of 128 Ω. The change in resistance is 13.3 Ω and change in length is 1.6 mm under tension. The gauge factor is |
| A. | 1.2 |
| B. | 1.6 |
| C. | 2.1 |
| D. | 2.6 |
| Answer» C. 2.1 | |
| 159. |
Assertion (A): A ballistic galvanometer is used to measure charge.Reason (R): In a flux meter, the damping is large. |
| 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 | |
| 160. |
In electronic voltmeters the measuring device is a |
| A. | θ |
| B. | 2θ |
| C. | 0.5θ |
| D. | 0.25θ |
| Answer» B. 2Œ∏ | |
| 161. |
A peak responding ac voltmeter using a half wave rectifier has been calibrated to read 1 V for 1 V rms sine wave input. If input is 1 V dc the reading will be |
| A. | 0.707 V |
| B. | 0.707 or 0 V |
| C. | 1.414 V |
| D. | 1.414 or 0 V |
| Answer» C. 1.414 V | |
| 162. |
The phenomenon of creep occurs in |
| A. | ammeters |
| B. | wattmeters |
| C. | moving coil instrument |
| D. | moving iron instrument |
| Answer» B. wattmeters | |
| 163. |
Two meters X and Y require 40 mA and 50 mA for full scale deflection. Then |
| A. | X is more sensitive |
| B. | Y is more sensitive |
| C. | both are equally sensitive |
| D. | it is not possible to determine from given data |
| Answer» E. | |
| 164. |
Two wattmeter method is suitable only for balanced loads. |
| A. | 1 |
| B. | |
| C. | about 6.82 V |
| D. | about 7.1 V |
| Answer» C. about 6.82 V | |
| 165. |
Which of these instrument does not have a control spring? |
| A. | Electrostatic voltmeters |
| B. | Power factor meter |
| C. | parallel |
| D. | perpendicular |
| Answer» E. | |
| 166. |
A polyphase wattmeter basically consists of two wattmeters. The moving system of two wattmeters |
| A. | are common |
| B. | are separate |
| C. | are generally common |
| D. | are generally separate |
| Answer» B. are separate | |
| 167. |
If an inductance L is connected in one arm of bridge and resistance R1, R2, R3 in other three arms |
| A. | the bridge is balanced for some specified value of frequency |
| B. | the bridge is balanced for some specific values of R1, R2, R3 |
| C. | 250 V |
| D. | 252 V |
| Answer» B. the bridge is balanced for some specific values of R1, R2, R3 | |
| 168. |
The signal to noise ratio in telemetry should be better than |
| A. | 5 db |
| B. | 10 db |
| C. | 25 db |
| D. | 60 db |
| Answer» E. | |
| 169. |
The temperature coefficient of resistance for a thermistor is |
| A. | low and negative |
| B. | low and positive |
| C. | high and negative |
| D. | high and positive |
| Answer» D. high and positive | |
| 170. |
A dynamometer wattmeter is suitable for both dc and ac. |
| A. | Ey |
| B. | Ey |
| C. | Ey1.5 |
| D. | Ey2 |
| Answer» B. Ey | |
| 171. |
Assertion (A): In loss of charge method, it is preferable to use an electronic voltmeter.Reason (R): The resistance of electronic voltmeter is very high. |
| 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 | |
| 172. |
To avoid creep in an energy meter |
| A. | two holes are cut in the disc on opposite sides of spindle |
| B. | the potential coil is made of very thin wire |
| C. | 0.25 Ω |
| D. | 0.5 Ω |
| Answer» D. 0.5 Œ© | |
| 173. |
For measuring temperatures below 800°C with high accuracy, the best instrument is |
| A. | GaAs junction diode thermometer |
| B. | platinum resistance thermometer |
| C. | 1 |
| D. | |
| Answer» E. | |
| 174. |
An ac bridge uses galvanometer as detector. |
| A. | 1 |
| B. | |
| C. | V I cos θ |
| D. | 3 VI cos θ |
| Answer» C. V I cos Œ∏ | |
| 175. |
Which of the following instruments can be used for dc as well ac upto a few MHz? Moving iron instrumentThermocouple instrumentInduction instrumentMoving coil instrument Select the correct answer as per following codes |
| A. | 2 only |
| B. | 2 and 3 only |
| C. | 1, 2 and 3 only |
| D. | 2 and 4 only |
| Answer» B. 2 and 3 only | |
| 176. |
Magnetic deflection sensitivity is defined as |
| A. | (Deflection)0.5/flux density |
| B. | none of the above |
| C. | Photoelectric |
| D. | Photovoltaic |
| Answer» B. none of the above | |
| 177. |
In 3 phase power measurement by two wattmeter method, both wattmeters had equal reading. The power factor of load is |
| A. | 1 |
| B. | 0.5 lagging |
| C. | 0.5 leading |
| D. | 0 |
| Answer» B. 0.5 lagging | |
| 178. |
In a Weston synchronoscope, the moving coil is connected across |
| A. | bus bar |
| B. | incoming alternator |
| C. | lamp |
| D. | fixed coils |
| Answer» B. incoming alternator | |
| 179. |
Assertion (A): The gall tinsley potentiometer is a coordinate potentiometer and has two exactly similar potentiometers.Reason (R): An ac potentiometer may measure the unknown voltage in polar form or rectangular coordinate form. |
| 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 | |
| 180. |
Which of the following is not correct in respect of electrostatic instrument? |
| A. | It is essentially a voltmeter |
| B. | It is suitable for only high voltages |
| C. | It has a uniform scale |
| D. | It can be used for both ac and dc |
| Answer» D. It can be used for both ac and dc | |
| 181. |
In indicating instruments the controlling torque is provided by a spring. |
| A. | 1 |
| B. | |
| C. | Kelvin's double bridge |
| D. | Wheatstone bridge |
| Answer» B. | |
| 182. |
Assertion (A): An RTD uses platinum coil.Reason (R): Platinum is a very stable material. |
| 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 | |
| 183. |
The stator of phase shifting transformer for use in conjunction with an ac potentiometer has a |
| A. | single phase winding |
| B. | two phase winding |
| C. | 3 phase winding |
| D. | either (a) or (c) |
| Answer» C. 3 phase winding | |
| 184. |
The sensitivity of electromagnetic digital flow meter can be increased by increasing |
| A. | circumferential width of rotor teeth |
| B. | radial depth of rotor teeth |
| C. | thickness of rotor teeth |
| D. | number of teeth |
| Answer» E. | |
| 185. |
Assertion (A): Hay's bridge in particularly suitable for measuring inductance having a comparatively low resistance.Reason (R): In Hay's bridge the value of frequency supply must be known. |
| 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 | |
| 186. |
Two wattmeter method of 3-phase power measurement can be used to find |
| A. | total active power and reactive power |
| B. | total active power, power factor, apparent power, and reactive power |
| C. | series |
| D. | parallel |
| Answer» E. | |
| 187. |
Assertion (A): A thermocouple transducer is based on Seeback effect.Reason (R): In a thermocouple transducer used for temperature measurement, the cold junction is usually kept in ice bath. |
| 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 | |
| 188. |
The flow rate of electrically conducting liquid without any suspended particle can not be measured by |
| A. | turbine flow meter |
| B. | electromagnetic flow meter |
| C. | ultrasonic flow meter |
| D. | thermistor based heat flow meter |
| Answer» E. | |
| 189. |
A transducer must have |
| A. | good dynamic response |
| B. | good sensitivity |
| C. | good resolution |
| D. | all of the above |
| Answer» E. | |
| 190. |
Consider the following Statements regarding resistance strain gauge The gauge factor is in the range of 2 to 5.The resistance changes due to change in specific resistance with strain.The resistance increases with increase in temperature. Of the above statements, which are correct? |
| A. | 1, 2, 3 |
| B. | 1 and 2 |
| C. | 2 and 3 |
| D. | 1 and 3 |
| Answer» E. | |
| 191. |
The circuit of figure is used to measure the value Rx. Ammeter resistance Ra = 0.1 Ω voltmeter resistance Rv = 5000 Ω. It Rx1 and Rx2, are the measured values of Rx with switch in position 1 and 2, the mean of Rx1, and Rx2, is |
| A. | 9.98 Ω |
| B. | 10 Ω |
| C. | 10.04 Ω |
| D. | 10.1 Ω |
| Answer» D. 10.1 Œ© | |
| 192. |
Basically a potentiometer is a device for |
| A. | comparing two votage |
| B. | measuring a voltage |
| C. | comparing two currents |
| D. | measuring a current |
| Answer» B. measuring a voltage | |
| 193. |
A 0-200 V voltmeter has an accuracy of 0.75% of full scale reading. If voltage measured is 100 V, the error is |
| A. | 0.03 |
| B. | 0.02 |
| C. | 0.015 |
| D. | 0.0075 |
| Answer» D. 0.0075 | |
| 194. |
Which of the following combinations is not used in thermocouple transducer measurement of temperature? |
| A. | Copper-constantan |
| B. | Iron-silver |
| C. | LP filter |
| D. | HP filter |
| Answer» E. | |
| 195. |
Two voltmeters 0-250 V each having resistances of 5 kΩ and 10 kΩ respectively and are connected in series. To ensure that neither of them goes beyond scale the total voltage which can be applied should be less than |
| A. | 500 V |
| B. | 400 V |
| C. | 375 V |
| D. | 250 V |
| Answer» D. 250 V | |
| 196. |
A hot wire instrument is not affected by stray magnetic fields. |
| 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 | |
| 197. |
Moving iron instrument can be used for ac only. |
| A. | moving coil instrument |
| B. | moving iron instrument |
| C. | dynamometer instrument |
| D. | none of the above |
| Answer» C. dynamometer instrument | |
| 198. |
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 | |
| 199. |
A CT is used to feed current coils of wattmeter, energy meter, power factor meter and an ammeter. Then |
| A. | all the coils are in series |
| B. | all coils are in parallel |
| C. | the coils are in series-parallel |
| D. | either (a) or (b) |
| Answer» B. all coils are in parallel | |
| 200. |
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. | |