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MCQOPTIONS
This section includes 2670 Mcqs, each offering curated multiple-choice questions to sharpen your Railways knowledge and support exam preparation. Choose a topic below to get started.
| 1651. |
The deflection expression\[\theta \propto {{V}^{2}}=\frac{dc}{d\theta }\]corresponds to |
| A. | moving iron type instrument |
| B. | electro dynamic type instruments |
| C. | electrostatic type instrument |
| D. | induction type instruments |
| Answer» D. induction type instruments | |
| 1652. |
Piezoelectric crystal is generally employed for the measurement of which one of the following? |
| A. | Flow |
| B. | Velocity |
| C. | Acceleration |
| D. | Temperature |
| Answer» D. Temperature | |
| 1653. |
Which one of the following statements is correct? The deflection of hot wire instrument depends on |
| A. | r. m. s. value of the a. c. current |
| B. | r. m. s. value of the a. c. voltage |
| C. | average value of the a. c. current |
| D. | average value of the a. c. voltage |
| Answer» B. r. m. s. value of the a. c. voltage | |
| 1654. |
In a single-phase power factor meter, the controlling torque is |
| A. | provided by spring control |
| B. | provided by gravity control |
| C. | provided by stuffiness of suspension |
| D. | not required |
| Answer» E. | |
| 1655. |
Which instrument has necessarily the 'square law type |
| A. | Permanent magnet moving coil. |
| B. | Hot wire instruments |
| C. | Moving iron repulsion |
| D. | None of the above |
| Answer» C. Moving iron repulsion | |
| 1656. |
Which one of the following digital voltmeters is most suitable to eliminate the effect of period noise? |
| A. | Ramp type digital voltmeter |
| B. | Integrating type digital voltmeter |
| C. | Successive approximation type digital voltmeter |
| D. | Servo type digital voltmeter |
| Answer» E. | |
| 1657. |
Which of the following bridges can be used for inductance measurement? 1. Maxwell's bridge 2 Schering bridge 3. We in-bridge 4.Hay's bridge 5. Wheatstone bridge Select the correct answer using the codes given below |
| A. | 1 and 2 |
| B. | 2 and 3 |
| C. | 3, 4 and 5 |
| D. | 1 and 4 |
| Answer» E. | |
| 1658. |
Using a C.T. has |
| A. | poorer overload capacity than a P.T. |
| B. | the same overload capacity as a P.T. |
| C. | a higher overload capacity than a P.T. |
| D. | none of the above |
| Answer» D. none of the above | |
| 1659. |
The bridge method commonly used for finding mutual inductance is |
| A. | Heavy side Campbell bridge |
| B. | Schering bridge |
| C. | De Sauty bridge |
| D. | Wien bridge |
| Answer» B. Schering bridge | |
| 1660. |
The pressure coil of a dynamometer type wattmeter is |
| A. | highly inductive |
| B. | highly resistive |
| C. | purely resistive |
| D. | purely inductive |
| Answer» C. purely resistive | |
| 1661. |
The Q-meter works on the principle of |
| A. | mutual inductance |
| B. | self inductance |
| C. | series resonance |
| D. | parallel resonance |
| Answer» D. parallel resonance | |
| 1662. |
Two 200 V D.C. voltmeters having resistances of \[15\,\,k-ohm\]and\[10\text{ }k-ohm\]are connected in series. The safe voltage which can be measured by this combination will be |
| A. | 400 V |
| B. | \[200\sqrt{2}\,V\] |
| C. | 200 V |
| D. | 100 V |
| Answer» D. 100 V | |
| 1663. |
The ratio of maximum displacement deviation to full scale deviation of the instrument is called the |
| A. | static sensitivity |
| B. | accuracy |
| C. | linearity |
| D. | precision |
| E. | dynamic deviation |
| Answer» E. dynamic deviation | |
| 1664. |
Which of the following does not have the same units as the others? The symbols have their usual meanings. |
| A. | \[\frac{L}{R}\] |
| B. | RC |
| C. | \[\sqrt{LC}\] |
| D. | \[\frac{1}{\sqrt{LC}}\] |
| Answer» E. | |
| 1665. |
\[{{W}_{1}}\]and\[{{W}_{2}}\]are the readings of two watt meters used to measure power of a 3-phase balanced load. The reactive power drawn by the load is |
| A. | \[{{W}_{1}}\]+\[{{W}_{2}}\] |
| B. | \[{{W}_{1}}-{{W}_{2}}\] |
| C. | \[\sqrt{3}\,\,({{W}_{1}}+{{W}_{2}})\] |
| D. | \[\sqrt{3}\,\,({{W}_{1}}-{{W}_{2}})\] |
| Answer» E. | |
| 1666. |
Half wave rectifier type AC meters are used as voltmeter They cannot be used as ammeters because |
| A. | pointer would oscillate with AC |
| B. | AC current would be too small to read |
| C. | AC current would be excessive |
| D. | AC is changed to DC |
| Answer» B. AC current would be too small to read | |
| 1667. |
Which of the following is not the method for reducing H residual inductance in resistors? |
| A. | Faraday's winding method |
| B. | Card wound resistor |
| C. | Chaperon winding method |
| D. | Curtis and Rower winding method |
| Answer» B. Card wound resistor | |
| 1668. |
The source of energy for operating an ohmmeter is obtained from? |
| A. | the line being measured |
| B. | any 120 volt source |
| C. | a rectifier cell |
| D. | a battery |
| Answer» E. | |
| 1669. |
An accurate ammeter must have a resistance of |
| A. | High value |
| B. | Low value |
| C. | Very low value |
| D. | None of the above |
| Answer» D. None of the above | |
| 1670. |
Capacitor potential transformers are used |
| A. | for primary voltage exceeding 100kv (Phase) |
| B. | because these are cheaper than the conventional type above a certain voltage |
| C. | for keeping the transformation ratio constant irrespective of the burden with certain adjustments |
| D. | all of the above |
| Answer» E. | |
| 1671. |
Quadrant type electrostatic instruments can be used for measurement of ac voltage |
| A. | only when heterostatically connected. |
| B. | only when idiostatically connected. |
| C. | in either heterostatic connection or idiostatic connection |
| D. | None of the above |
| Answer» C. in either heterostatic connection or idiostatic connection | |
| 1672. |
Before connecting a meter to measure an unknown current or voltage, it is best to |
| A. | start with the highest range and work down |
| B. | start with the lowest range and work down |
| C. | select an estimated mid-range |
| D. | use the trial and error method |
| Answer» B. start with the lowest range and work down | |
| 1673. |
Electrostatic instruments |
| A. | can be used on dc only |
| B. | when used on ac measure rms value whatever the waveform |
| C. | are highly sensitive to eddy current errors |
| D. | none of the above |
| Answer» C. are highly sensitive to eddy current errors | |
| 1674. |
Electrodynamometers are used extensively for the measurement of |
| A. | magnetic lines of force |
| B. | resistivity |
| C. | capacitor networks |
| D. | power |
| Answer» E. | |
| 1675. |
In indicating instruments the damping is usually adjusted |
| A. | at critical value |
| B. | to the value slightly higher than critical value |
| C. | to the value slightly higher than critical value value |
| D. | to any value |
| Answer» C. to the value slightly higher than critical value value | |
| 1676. |
A man hold both the terminals of a 500 V megger, but still safe due to |
| A. | high voltage |
| B. | very low current |
| C. | high resistance of the body |
| D. | low resistance of the body |
| Answer» C. high resistance of the body | |
| 1677. |
A negative sequence relay is commonly used to protect |
| A. | an alternator |
| B. | a transformer |
| C. | a transmission line |
| D. | a bus bar |
| Answer» B. a transformer | |
| 1678. |
A 4-point starter is used to start and control the speed of a |
| A. | dc shunt motor with armature resistance control |
| B. | dc shunt motor with field weakening control |
| C. | dc series motor |
| D. | dc compound motor |
| Answer» B. dc shunt motor with field weakening control | |
| 1679. |
The DC motor, which can provide zero-speed regulation at full load without any controller, is |
| A. | series |
| B. | shunt |
| C. | cumulative compound |
| D. | differential compound |
| Answer» B. shunt | |
| 1680. |
In a transformer, zero voltage regulation at full load is |
| A. | not possible |
| B. | possible at unity power factor load |
| C. | possible at leading power factor load |
| D. | possible at lagging power factor load |
| Answer» D. possible at lagging power factor load | |
| 1681. |
The transformer noise is mainly because of |
| A. | Cooling oil |
| B. | Sinusoidal current |
| C. | Magnetic flux |
| D. | All of the above |
| Answer» C. Magnetic flux | |
| 1682. |
For a single phase capacitor start induction motor which of the following statements is valid? |
| A. | The capacitor is used for power factor improvement. |
| B. | The direction of rotation can be changed by reversing the main winding terminals. |
| C. | The direction of rotation cannot be changed. |
| D. | The direction of rotation can be changed by interchanging the supply terminals. |
| Answer» C. The direction of rotation cannot be changed. | |
| 1683. |
DC Motor Yoke is generally made of |
| A. | Wood |
| B. | Copper |
| C. | Aluminium |
| D. | Steel |
| Answer» D. Steel | |
| 1684. |
Cross magnetization affects which of the following? |
| A. | Commutation |
| B. | Reduction in main field flux |
| C. | Reduces the terminal voltage |
| D. | Both 2 and 3 |
| Answer» B. Reduction in main field flux | |
| 1685. |
No load saturation characteristics are plotted between |
| A. | No load voltage and field current |
| B. | No load voltage and armature current |
| C. | Short circuit current and field current |
| D. | Short circuit current and armature current |
| Answer» B. No load voltage and armature current | |
| 1686. |
The effect of _____ on main field flux is armature reaction? |
| A. | Armature mmf |
| B. | Armature current |
| C. | Armature flux |
| D. | All of the above |
| Answer» B. Armature current | |
| 1687. |
Equalizer rings are used in which of the followings? |
| A. | Lap winding |
| B. | Wave winding |
| C. | Both 1 and 2 |
| D. | None of the above |
| Answer» D. None of the above | |
| 1688. |
Inter pole winding is connected in____? |
| A. | Series with armature |
| B. | Series with main poles |
| C. | Parallel with armature |
| D. | Parallel with main poles |
| Answer» D. Parallel with main poles | |
| 1689. |
Which of the following windings are necessary in case call dc machines? |
| A. | Closed winding |
| B. | Lap winding |
| C. | Wave winding |
| D. | Open type winding |
| Answer» B. Lap winding | |
| 1690. |
Which of the bearings and their uses are correct |
| A. | Ball bearings \[\to\] small machines |
| B. | Roller bearings \[\to\] large machines |
| C. | Both A and B |
| D. | Neither 1 nor 2 |
| Answer» D. Neither 1 nor 2 | |
| 1691. |
A DC generator without commentator is a |
| A. | AC generator |
| B. | DC motor |
| C. | DC generator |
| D. | Induction motor |
| Answer» C. DC generator | |
| 1692. |
Hysteresis loop represents the area of |
| A. | Copper loss |
| B. | Eddy current loss |
| C. | Hysteresis loss |
| D. | Total iron losses |
| Answer» B. Eddy current loss | |
| 1693. |
The emf induced in the dc generator armature winding is |
| A. | AC |
| B. | DC |
| C. | AC and DC |
| D. | None of the above |
| Answer» B. DC | |
| 1694. |
Eddy current loss will depends on |
| A. | Frequency |
| B. | Flux density |
| C. | Thickness |
| D. | All of the above |
| Answer» B. Flux density | |
| 1695. |
If field current is decreased in shunt dc motor, the speed of the motor |
| A. | remains same. |
| B. | increases. |
| C. | decreases. |
| D. | none of the above. |
| Answer» E. | |
| 1696. |
The equivalent circuit of a transformer has leakage reactance?s \[{{X}_{1}},\,\,X{{'}_{2}}\] and magnetizing reactance \[{{X}_{M}}\] , Their magnitudes satisfy |
| A. | \[{{X}_{1}}>>X{{'}_{2}}>>{{X}_{M}}\] |
| B. | \[{{X}_{1}}=X{{'}_{2}}<<{{X}_{M}}\] |
| C. | \[{{X}_{1}}\approx X{{'}_{2}}>>{{X}_{M}}\] |
| D. | \[{{X}_{1}}\approx X{{'}_{2}}<<{{X}_{M}}\] |
| Answer» D. \[{{X}_{1}}\approx X{{'}_{2}}<<{{X}_{M}}\] | |
| 1697. |
For the parallel operation of three phase transformers, which among the following connection is not applicable? |
| A. | \[\Delta -\Delta\] to\[YY\] |
| B. | \[YA\]to \[A-Y\] |
| C. | \[YY\]to\[YY\] |
| D. | None of these |
| Answer» D. None of these | |
| 1698. |
The constant voltage transformers are most commonly used in |
| A. | Personal computers |
| B. | Arc welding |
| C. | Power distribution |
| D. | Electric cars |
| Answer» C. Power distribution | |
| 1699. |
In a single phase induction motor, the motor speed on no load is |
| A. | Almost equal to its synchronous speed |
| B. | Less than its synchronous speed |
| C. | Greater than synchronous speed |
| D. | None of these |
| Answer» D. None of these | |
| 1700. |
The phase shift in a star-star connected three phase transformer is |
| A. | 0 degree |
| B. | 30 degree |
| C. | 60 degree |
| D. | 120 degree |
| Answer» C. 60 degree | |