MCQOPTIONS
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MCQOPTIONS
This section includes 657 Mcqs, each offering curated multiple-choice questions to sharpen your Testing Subject knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Assertion (A): Moving iron instrument can be used on ac or dc.Reason (R): In a moving iron instrument deflecting torque 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 | |
| 2. |
Which of these instruments has highest power consumption? |
| A. | Dynamometer |
| B. | Electrostatic |
| C. | Moving coil |
| D. | Hot wire |
| Answer» E. | |
| 3. |
A thermocouple instrument can be used over a very wide frequency range. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 4. |
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 | |
| 5. |
In a thermocouple temperature transducer, the output voltage is usually measured by |
| A. | high resistance ammeter |
| B. | high resistance voltmeter |
| C. | high resistance milli-voltmeter |
| D. | none of the above |
| Answer» D. none of the above | |
| 6. |
If reference sound pressure P₀ is 2 x 10¯⁵ N/m², a sound pressure of 90 dB is equal to |
| A. | 0.632 N/m² |
| B. | 0.707 N/m² |
| C. | 0.835 N/m² |
| D. | 0.925 N/m² |
| Answer» B. 0.707 N/m² | |
| 7. |
An induction wattmeter can be used for ac only. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 8. |
In low power factor wattmeter, the pressure coil is connected |
| A. | to the supply side of current coil |
| B. | to the load side of current coil |
| C. | in either (a) or (b) |
| D. | across the mains |
| Answer» C. in either (a) or (b) | |
| 9. |
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 | |
| 10. |
Which of the following combinations is not used in thermocouple transducer measurement of temperature? |
| A. | Iron-constantan |
| B. | Chromel-aluminium |
| C. | Copper-constantan |
| D. | Iron-silver |
| Answer» E. | |
| 11. |
Moving iron instrument can be used for ac only. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |
| 12. |
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 Ω | |
| 13. |
A temperature sensistive transducer is subjected to sudden temperature change. It takes 10 seconds for transducer to reach equilibrium condition (five times time constant). The time taken to reach half of temperature difference will be |
| A. | 1.38 s |
| B. | 5 s |
| C. | 8.62 s |
| D. | 0.9 s |
| Answer» B. 5 s | |
| 14. |
A hot wire instrument is not affected by stray magnetic fields. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 15. |
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 | |
| 16. |
A sinusoidal ac voltage of amplitude 100 V is applied to a rectifying device which offers 10 Ω resistance in forward direction and infinite resistance in reverse direction. The reading on hot wire ammeter will be |
| A. | 10 A |
| B. | 5 A |
| C. | 3.185 A |
| D. | 1.414 A |
| Answer» C. 3.185 A | |
| 17. |
The sensitivity of a voltmeter using 0-5 mA meter movement is |
| A. | 50 Ω/V |
| B. | 100 Ω/V |
| C. | 200 Ω/V |
| D. | 500 Ω/V |
| Answer» D. 500 Ω/V | |
| 18. |
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 | |
| 19. |
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 | |
| 20. |
When measuring phase angle between two waves using a CRO, the time base generator is connected to |
| A. | X plate |
| B. | Y plate |
| C. | both X and Y plate |
| D. | neither X nor Y plates |
| Answer» E. | |
| 21. |
In Maxwell's bridge the unknown inductance is measured by comparing it with a standard capacitor. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |
| 22. |
In portable instruments, damping is provided by |
| A. | spring |
| B. | gravity |
| C. | eddy current |
| D. | either (a) or (c) |
| Answer» B. gravity | |
| 23. |
Four voltmeters have following specifications. If accuracy is main consideration which is the best? |
| A. | 100 V, 2 mA |
| B. | 100 V, 100 mA |
| C. | 100 V, 1 mA |
| D. | 100 V, 0.1 mA |
| Answer» E. | |
| 24. |
In an induction wattmeter, the shading bands are made of non conducting material. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» C. May be True or False | |
| 25. |
A power factor meter has |
| A. | one current and one pressure circuit |
| B. | one current circuit and two pressure circuits |
| C. | two current circuits and two pressure circuits |
| D. | two current circuits and one pressure circuit |
| Answer» C. two current circuits and two pressure circuits | |
| 26. |
The dimensions of force are |
| A. | MLT¯² |
| B. | ML¯¹T¯² |
| C. | MLT¯¹ |
| D. | ML²T¯² |
| Answer» B. ML¯¹T¯² | |
| 27. |
Consider the following statements: In a differential amplifier using JFET, the differential output offset is due to 1. mismatch between FET parameters2. difference in values of resistances used in circuit3. variation in supply voltage. Of the statements, the correct statements are |
| A. | 1 and 2 |
| B. | 1, 2, 3 |
| C. | 2, 3 |
| D. | 1, 3 |
| Answer» B. 1, 2, 3 | |
| 28. |
A coil resonates at 1 MHz with a resonating capacitance of 72 pF. At 500 pF, resonance is obtained with a resonating capacitor of 360 pF. The self capacitance of coil is |
| A. | 12 pF |
| B. | 24 pF |
| C. | 30 pF |
| D. | 72 pF |
| Answer» C. 30 pF | |
| 29. |
A current of 3.25 A is flowing through a resistance of 34.98 Ω. The voltage drop across resistance to the appropriate number of significant figures is |
| A. | 113.685 V |
| B. | 113.68 V |
| C. | 113.6 V |
| D. | 114 V |
| Answer» E. | |
| 30. |
Which one of the following effects is used in measuring power? |
| A. | Seeback |
| B. | Ferrari |
| C. | Induction |
| D. | Hall |
| Answer» D. Hall | |
| 31. |
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 | |
| 32. |
The angle δ for a mica capacitor is about |
| A. | 25° |
| B. | 15° |
| C. | 5° |
| D. | 1° |
| Answer» E. | |
| 33. |
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 | |
| 34. |
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. | |
| 35. |
In a megger the controlling torque is provided by |
| A. | spring |
| B. | gravity |
| C. | coil |
| D. | eddy current |
| Answer» D. eddy current | |
| 36. |
A vibration galvanometer is a |
| A. | moving coil instrument |
| B. | moving iron instrument |
| C. | dynamometer instrument |
| D. | induction instrument |
| Answer» B. moving iron instrument | |
| 37. |
It is necessary to measure the amplitudes of two signals and also the phase difference between them. This can be done by using a |
| A. | phase meter |
| B. | waveform meter |
| C. | vector voltmeter |
| D. | digital voltmeter |
| Answer» C. vector voltmeter | |
| 38. |
Loading effect is primarily caused by instruments having |
| A. | high resistance |
| B. | high sensitivity |
| C. | low sensitivity |
| D. | high range |
| Answer» D. high range | |
| 39. |
Assertion (A): The trigger circuit of a CRO is excited by the same signal as Y plates.Reason (R): The time base generator develops a saw tooth voltage. |
| 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 | |
| 40. |
Which of the following voltmeters would you use for measuring voltage across 20 kΩ resistance? |
| A. | Voltmeter having a resistance of 5 kΩ |
| B. | Voltmeter having a sensitivity of 1 kW/V |
| C. | Voltmeter having sensitivity of 10 kW/V |
| D. | None of the above |
| Answer» D. None of the above | |
| 41. |
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 | |
| 42. |
In a dynamometer 3 phase power factor meter, the planes of the two moving coils are at |
| A. | 60° |
| B. | 0° |
| C. | 120° |
| D. | 90° |
| Answer» D. 90° | |
| 43. |
Consider the following instruments1. Tangent galvanometer2. Rayleigh current balance3. Household energy meter4. Hot 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 | |
| 44. |
Radiation pyrometer is used to measure temperature in the range of |
| A. | -200 to 500° C |
| B. | 0 to 500° C |
| C. | 500 to 1200° C |
| D. | 1200 to 2500° C |
| Answer» E. | |
| 45. |
In ac bridge measurements, 'Wagner ground' means |
| A. | a special RC connection to eliminate stray magnetic effects |
| B. | a special RC connection to eliminate stray capacitance effects |
| C. | an unwanted and unintended ground connection |
| D. | a large metal plate buried in ground connected to one corner of bridge |
| Answer» C. an unwanted and unintended ground connection | |
| 46. |
The scale of PMMC instrument is linear. |
| A. | True |
| B. | False |
| C. | May be True or False |
| D. | can't say |
| Answer» B. False | |
| 47. |
Magnetic field intensity has the dimensions |
| A. | IL |
| B. | I²L |
| C. | IL¯¹ |
| D. | IL¯² |
| Answer» D. IL¯² | |
| 48. |
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 | |
| 49. |
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. | |
| 50. |
Assertion (A): For best results the system of a D'Arsonval galvanometer should be slightly under damped.Reason (R): Degree of damping affects the time taken by the instrument to come to final position. |
| 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 | |