MCQOPTIONS
Saved Bookmarks
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. |
A TRIAC can be turned on : |
| A. | by applying a positive signal to gate |
| B. | by applying a negative signal to gate |
| C. | by applying either positive or negative signal to gate |
| D. | none of the above |
| Answer» D. none of the above | |
| 2. |
In auxiliary commutated chopper, the peak value of thyristor current is |
| A. | equal to peak value of load current |
| B. | equal to peak value of capacitor current |
| C. | sum of peak value of load current and capacitor current |
| D. | none of the above |
| Answer» D. none of the above | |
| 3. |
The output wave of a cycloconverter consists of a number of segments derived from the input wave. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 4. |
Which chopper circuit operates in quadrants 1 and 4? |
| A. | A |
| B. | B |
| C. | D |
| D. | E |
| Answer» D. E | |
| 5. |
A single phase cycloconverter with centre tapped input transformer requires |
| A. | 2 thyristors |
| B. | 4 thyristors |
| C. | 8 thyristors |
| D. | either 2 or 4 thyristors |
| Answer» C. 8 thyristors | |
| 6. |
Assertion (A): For a solenoid having N turns, .Reason (R): For all magnetic materials, B increases linearly with I. |
| 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 but R is false |
| D. | A is false but R is true |
| Answer» D. A is false but R is true | |
| 7. |
Assertion (A): In a perfect capacitor, the current density is given by 0E0 'rcos( t + 90 ), where r' is real part of dielectric constant.Reason (R): In a perfect capacitor, dielectric losses are zero. |
| 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 but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not correct explanation of A | |
| 8. |
Assertion (A): In a parallel plate capacitor having area of plate 1 m2 and plate separation 1 m, the capacitance C and resistance R are given by C = 0 'r and R = where is frequency, r' and r" are real and imaginary parts of dielectric constant.Reason (R): The imaginary part of electric constant is responsible for dielectric losses. |
| 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 but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true but R is not correct explanation of A | |
| 9. |
In the context of error detection in satellite transmission, ARQ stands for |
| A. | Automatic Repeat Request |
| B. | Automatic Relay Request |
| C. | Accelerated Recovery Request |
| D. | Automatic Radiation Quenching |
| Answer» B. Automatic Relay Request | |
| 10. |
Assertion (A): The sign and magnitude of displacement can be measured by an LVDT.Reason (R): LVDT is based on the principle of mutual inductance. |
| 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 | |
| 11. |
Assertion (A): CRO can be used to study waveshape accurately.Reason (R): Input impedance of a CRO 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 | |
| 12. |
LVDT is used to measure |
| A. | displacement |
| B. | pressure |
| C. | temperature |
| D. | any of the above |
| Answer» B. pressure | |
| 13. |
An electrostatic voltmeter is suitable for |
| A. | low voltage at high frequency |
| B. | high voltage |
| C. | low voltage at low frequency |
| D. | all ac and dc voltages |
| Answer» C. low voltage at low frequency | |
| 14. |
In Maxwell's bridge the unknown inductance is measured by comparing it with a standard capacitor. |
| A. | True |
| B. | False |
| Answer» C. | |
| 15. |
The operating voltage of a megger is about |
| A. | 100 V |
| B. | 12 V |
| C. | 6 V |
| D. | 1 V |
| Answer» B. 12 V | |
| 16. |
An ohmmeter is a |
| A. | moving coil instrument |
| B. | moving iron instrument |
| C. | dynamometer instrument |
| D. | induction instrument |
| Answer» B. moving iron instrument | |
| 17. |
The scale of thermocouple instrument is linear. |
| A. | True |
| B. | False |
| Answer» C. | |
| 18. |
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. | |
| 19. |
While calibrating an ammeter by a dc potentiometer it is necessary to use a standard resistance. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 20. |
Which is the displacement transducer with excellent sensitivity, linearity and resolution? |
| A. | Incremental encoder |
| B. | Absolute encoder |
| C. | LVDT |
| D. | Strain gauge |
| Answer» D. Strain gauge | |
| 21. |
If J is moment of Inertia, D is damping constant, C is spring constant, G is displacement constant and I is current throught the coil of DArsonval galvanometer, the equation of motion is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/232-66-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/232-66-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/232-66-3.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/232-66-4.png"> |
| Answer» C. <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/232-66-3.png"> | |
| 22. |
The term 'Poisson's ratio' is connected with |
| A. | strain gauge |
| B. | LVDT |
| C. | Bourden tube |
| D. | capacitance transducer |
| Answer» B. LVDT | |
| 23. |
Which of the following is active transducer? |
| A. | Photoelectric |
| B. | Photovoltaic |
| C. | Photoconductive |
| D. | Photoemissive |
| Answer» C. Photoconductive | |
| 24. |
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 | |
| 25. |
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 | |
| 26. |
If the load current is high, the pressure coil of wattmeter should be connected directly across the load. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 27. |
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 | |
| 28. |
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 | |
| 29. |
Harmonic distortion analyser |
| A. | measures amplitude of each harmonic |
| B. | measures rms value of fundamental frequency component |
| C. | measures rms value of all harmonics except fundamental frequency |
| D. | displays rms value of each harmonic on screen of CRO |
| Answer» D. displays rms value of each harmonic on screen of CRO | |
| 30. |
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 | |
| 31. |
Which of the following, is not a piezoelectric material? |
| A. | Rochelle salt |
| B. | Quartz |
| C. | Lithium sulphate |
| D. | Sodium bicarbonate |
| Answer» E. | |
| 32. |
It is required to measure the true open circuit emf of a battery. The best device is |
| A. | dc voltmeter |
| B. | ammeter and known resistance |
| C. | dc potentiometer |
| D. | either (a) or (c) |
| Answer» D. either (a) or (c) | |
| 33. |
The material used in RTD is |
| A. | linear |
| B. | aluminium |
| C. | silver |
| D. | platinum |
| Answer» E. | |
| 34. |
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 | |
| 35. |
If two time varying signals of equal magnitudes and 90 phase displacement are applied to X and Y plates of CRO, the display will be |
| A. | a straight line |
| B. | a circle |
| C. | an ellipse |
| D. | a rectangle |
| Answer» C. an ellipse | |
| 36. |
Measurement of non-electrical quantity involves the following subsystems Amplifier blockDisplay blockInstrumentation blockTransducer block The correct sequence of these blocks is |
| A. | 4, 1, 3, 2 |
| B. | 4, 3, 1, 2 |
| C. | 1, 3, 2, 4 |
| D. | 1, 2, 3, 4 |
| Answer» B. 4, 3, 1, 2 | |
| 37. |
Wagner earthing device eliminates |
| A. | all stray capacitance in the circuit |
| B. | stray capacitances between components |
| C. | stray capacitance between detector terminal and ground |
| D. | mutual coupling between components |
| Answer» D. mutual coupling between components | |
| 38. |
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 | |
| 39. |
Assertion (A): A photovoltaic cell is greatly affected by temperature.Reason (R): Both germanium and silicon can be used for photovoltaic cells. |
| 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. |
In figure the values of Rx and Cx are |
| A. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/242-283-2.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/242-283-3.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/242-283-4.png"> |
| D. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/242-283-5.png"> |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/242-283-3.png"> | |
| 41. |
A dynamometer wattmeter is suitable for both dc and ac. |
| A. | True |
| B. | False |
| Answer» B. False | |
| 42. |
The method of frequency compensation in moving iron voltmeter is |
| A. | to use a capacitor in series with coil |
| B. | to connect a capacitor in parallel with coil |
| C. | to connect a capacitor in parallel with series resistance |
| D. | none of the above |
| Answer» D. none of the above | |
| 43. |
An oscilloscope has an input impedance consisting of 1 M&ohm; and 20 pF is parallel. A high impedance probe connected to input of this oscilloscope has a 10 M&ohm; series resistance. This 10 M&ohm; series resistance |
| A. | may not be shunted |
| B. | should be shunted by 2 pF capacitor |
| C. | should be shunted by 20 pF capacitor |
| D. | should be shunted by 200 pF capacitor |
| Answer» C. should be shunted by 20 pF capacitor | |
| 44. |
Which of the following is used as detector in audio frequency ac bridges? |
| A. | AC voltmeter |
| B. | CRO |
| C. | Head phones |
| D. | Vibration galvanometer |
| Answer» D. Vibration galvanometer | |
| 45. |
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 | |
| 46. |
DC voltage of the order of a few mV can be accurately of measured by |
| A. | PMMC voltmeters |
| B. | moving iron voltmeter |
| C. | null balancing potentiometer |
| D. | electrostatic voltmeter |
| Answer» D. electrostatic voltmeter | |
| 47. |
A Weston frequency meter is |
| A. | moving coil instrument |
| B. | moving iron instrument |
| C. | dynamometer instrument |
| D. | induction instrument |
| Answer» C. dynamometer instrument | |
| 48. |
If d1, d2, ..., dn are n individual deviations, the standard deviation is |
| A. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/230-4-1.png"> |
| B. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/230-4-2.png"> |
| C. | <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/230-4-3.png"> |
| D. | none of the above |
| Answer» B. <img src="/_files/images/electronics-and-communication-engineering/measurements-and-instrumentation/230-4-2.png"> | |
| 49. |
The 10 MHz in the specification of CRO means that |
| A. | the sweep frequency is 10 MHz |
| B. | the frequency of input signal should not be more than 10 MHz |
| C. | the vertical amplifier has been designed for 10 MHz |
| D. | none of the above |
| Answer» B. the frequency of input signal should not be more than 10 MHz | |
| 50. |
Rayleigh current balance is an absolute instrument. |
| A. | True |
| B. | False |
| Answer» B. False | |