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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.
| 1701. |
In washing machines, most commonly used motors are |
| A. | Split phase induction motors |
| B. | Slip ring induction motors |
| C. | Capacitor start induction motors |
| D. | Shaded pole induction motors |
| Answer» E. | |
| 1702. |
Open circuit test is to be performed on transformer to find |
| A. | Constant losses |
| B. | Copper losses |
| C. | Both [a] and [b] |
| D. | None of these |
| Answer» C. Both [a] and [b] | |
| 1703. |
For large low voltage transformers, the most commonly used connections are |
| A. | Star - star connection |
| B. | Delta - delta connection |
| C. | V connection |
| D. | All of these |
| Answer» C. V connection | |
| 1704. |
Which three phase connection can be used in a transformer to introduce a phase difference of 30° between its output and corresponding input time voltages? |
| A. | Star - Star |
| B. | Star - Delta |
| C. | Delta - Delta |
| D. | Delta - Zigzag |
| Answer» D. Delta - Zigzag | |
| 1705. |
The most commonly used connections for power systems as a step - up and step - down transformers are |
| A. | Star - delta, star - star |
| B. | Delta - star, star - delta |
| C. | Star - star, delta - delta |
| D. | Star - delta, delta - star |
| Answer» E. | |
| 1706. |
The load carried by \[V-V\] connection is |
| A. | 47.7% of the original load |
| B. | 57.7% of the original load |
| C. | 67.7% of the original load |
| D. | 87.7% of the original load |
| Answer» E. | |
| 1707. |
In Scott connection, the voltage across the teaser leads the mains by |
| A. | 30 degree |
| B. | 60 degree |
| C. | 90 degree |
| D. | 120 degree |
| Answer» E. | |
| 1708. |
Most familiar application of zig-zag transformer is as |
| A. | Ground reference on an ungrounded system |
| B. | Converting single phase to two phase |
| C. | Reducing harmonics |
| D. | All of these |
| Answer» D. All of these | |
| 1709. |
In double delta transformation, a double delta refers to the case where there are two delta transformations in |
| A. | Parallel |
| B. | Series |
| C. | Both series and parallel |
| D. | Neither series nor parallel |
| Answer» E. | |
| 1710. |
In a synchronous generator operating at zero power factor lagging, the effect of armature reaction is |
| A. | magnetizing |
| B. | demagnetizing |
| C. | cross-magnetizing |
| D. | both magnetizing and cross-magnetizing |
| Answer» D. both magnetizing and cross-magnetizing | |
| 1711. |
In dc machines, the armature windings are placed on the rotor because of the necessity for |
| A. | electromechanical energy conversion |
| B. | generation of voltage |
| C. | commutation |
| D. | development of torque |
| Answer» E. | |
| 1712. |
Leakage flux in an induction motor is |
| A. | flux that leaks through the machine |
| B. | flux that links both stator and rotor windings |
| C. | flux that links none of the windings |
| D. | flux that links the stator winding or the rotor winding but not both |
| Answer» B. flux that links both stator and rotor windings | |
| 1713. |
The slip of an induction motor normally does not depend on |
| A. | rotor speed |
| B. | synchronous speed |
| C. | shaft torque |
| D. | core-loss component |
| Answer» B. synchronous speed | |
| 1714. |
Kirchoff's first law, Le., S i = 0 at a junction, deals with the conservation of |
| A. | charge |
| B. | energy |
| C. | momentum |
| D. | angular momentum |
| Answer» B. energy | |
| 1715. |
One Kilowatt hour is equal to |
| A. | \[36\times {{10}^{5}}\,joule\] |
| B. | \[36\times {{10}^{3}}\,joule\] |
| C. | \[{{10}^{3}}\,joule\] |
| D. | \[{{10}^{5}}\,joule\] |
| Answer» B. \[36\times {{10}^{3}}\,joule\] | |
| 1716. |
Internal resistance of ideal current source is |
| A. | Zero |
| B. | Infinite |
| C. | Finite |
| D. | 100 ohms |
| Answer» C. Finite | |
| 1717. |
Consider the following two statements. [A] Kirchoff's junction law follows from conservation of charge. [B] Kirchoff's loop law follows from conservative nature of electric field. |
| A. | Both A and B are correct |
| B. | A is correct but B is wrong |
| C. | B is correct but A is wrong |
| D. | Both A and B are wrong |
| Answer» C. B is correct but A is wrong | |
| 1718. |
Super position theorem is not applicable for |
| A. | Current calculations |
| B. | Voltage calculations |
| C. | Power calculations |
| D. | None of the above |
| Answer» D. None of the above | |
| 1719. |
KVL works on the principle of |
| A. | Law of conservation of charge |
| B. | Law of conservation of energy |
| C. | Both |
| D. | None of the above |
| Answer» C. Both | |
| 1720. |
Average power taken by the pure capacitor is |
| A. | Zero |
| B. | Minimum |
| C. | Maximum |
| D. | Any of the above |
| Answer» B. Minimum | |
| 1721. |
Internal resistance of ideal voltage source is |
| A. | Zero |
| B. | Infinite |
| C. | Finite |
| D. | 100 ohms |
| Answer» B. Infinite | |
| 1722. |
Mesh analysis is applicable for |
| A. | Planar networks |
| B. | Non planar networks |
| C. | Both planar & non-planar networks. |
| D. | Neither planar nor non planar networks |
| Answer» B. Non planar networks | |
| 1723. |
Which of the following are the passive elements? |
| A. | Resistor |
| B. | Bulb |
| C. | Both |
| D. | None of these. |
| Answer» D. None of these. | |
| 1724. |
Power dissipation in ideal inductor is |
| A. | Maximum |
| B. | Minimum |
| C. | Zero |
| D. | A finite value |
| Answer» D. A finite value | |
| 1725. |
Which of the followings is/are active element? |
| A. | Voltage source |
| B. | Current source |
| C. | Both |
| D. | None of these. |
| Answer» D. None of these. | |
| 1726. |
The unit of capacitance of a capacitor is |
| A. | joule |
| B. | henry |
| C. | farad |
| D. | ampere |
| Answer» D. ampere | |
| 1727. |
1 F is theoretically equal to |
| A. | 1 ohm of resistance |
| B. | Ratio of 1 V to 1 C |
| C. | Ratio of 1 C to 1 V |
| D. | None of these |
| Answer» D. None of these | |
| 1728. |
A capacitor carries a charge of \[0.1C\,\,at\,\,5\,\,V\]Its capacitance is |
| A. | 0.02 F |
| B. | 0.5 F |
| C. | 0.05 F |
| D. | 0.2 F |
| Answer» B. 0.5 F | |
| 1729. |
To a highly inductive circuit, a small capacitance is added in series. The angle between voltage and current will |
| A. | increase |
| B. | Decrease |
| C. | remain nearly the same |
| D. | become in determinant |
| Answer» C. remain nearly the same | |
| 1730. |
Which of the following statements associated with capacitors is wrong? |
| A. | A capacitor resists an abrupt change in the voltage across it in a manner analogous to the way a spring resists abrupt change in the current flowing through it. |
| B. | A capacitor resists an abrupt change in the current flowing through it. |
| C. | It is impossible to change the voltage across capacitor ' by a finite amount in zero time, for this requires infinite current through the capacitor. |
| D. | A finite amount of energy can be stored in a capacitor even if the current through the capacitor is zero, such as when the voltage across it is a constant. |
| Answer» C. It is impossible to change the voltage across capacitor ' by a finite amount in zero time, for this requires infinite current through the capacitor. | |
| 1731. |
A solid sphere made of insulating material has a radius R and has a total charge Q distributed uniformly in its volume. What is the magnitude of the electric field intensity, E, at a distance r (0 < r < R) inside the sphere? |
| A. | \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Qr}{{{R}^{3}}}\] |
| B. | \[\frac{3}{4\pi {{\varepsilon }_{0}}}\frac{Qr}{{{R}^{3}}}\] |
| C. | \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{Q}{{{r}^{2}}}\] |
| D. | \[\frac{1}{4\pi {{\varepsilon }_{0}}}\frac{QR}{{{r}^{3}}}\] |
| Answer» B. \[\frac{3}{4\pi {{\varepsilon }_{0}}}\frac{Qr}{{{R}^{3}}}\] | |
| 1732. |
The number of chords in the graph of the given circuit will be |
| A. | 3 |
| B. | 4 |
| C. | 5 |
| D. | 6 |
| Answer» B. 4 | |
| 1733. |
If E is the electric field intensity then \[\Delta .(\Delta \times E)\] is equal to |
| A. | \[E\] |
| B. | \[|\overrightarrow{E}|\] |
| C. | null vector |
| D. | zero |
| Answer» D. zero | |
| 1734. |
The RMS value of the voltage u(t} = 3 + 4cos (3t is |
| A. | \[\sqrt{17}V\] |
| B. | \[5V\] |
| C. | \[7V\] |
| D. | \[(3+2\sqrt{2})\,\,V\] |
| Answer» B. \[5V\] | |
| 1735. |
Two charges are at a distance d apart. If a copper plate (conducting medium) of thickness \[\frac{d}{2}\]is placed between them, the effective force will be |
| A. | 2F |
| B. | F/2 |
| C. | 0 |
| D. | \[\sqrt{2F}\] |
| Answer» B. F/2 | |
| 1736. |
As the temperature of a conductor increases, its resistivity and conductivity change. The ratio of resistivity to conductivity |
| A. | increases |
| B. | decreases |
| C. | remains constant |
| D. | may increase or decrease depending on the actual temperature. |
| Answer» D. may increase or decrease depending on the actual temperature. | |
| 1737. |
The electric field due to a uniformly charged sphere of radius R as a function of the distance from its centre is represented graphically by |
| A. | electric field is zero but potential is not zero |
| B. | electric field is not zero but potential is zero |
| C. | neither electric field nor potential is zero |
| D. | None of these |
| Answer» C. neither electric field nor potential is zero | |
| 1738. |
Figures below show regular hexagons, with charges at the vertices, hi which of the following cases the electric field at the centre is not zero. (1) (2) (3) (4) |
| A. | 1 |
| B. | 2 |
| C. | 3 |
| D. | 4 |
| Answer» E. | |
| 1739. |
There is a point charge +q inside a hollow sphere and a point charge -q just outside its surface. The total flux passing through the sphere |
| A. | \[\frac{-q}{{{\in }_{0}}}\] |
| B. | \[\frac{q}{{{\in }_{0}}}\] |
| C. | \[\frac{2q}{{{\in }_{0}}}\] |
| D. | zero. |
| Answer» D. zero. | |
| 1740. |
In which of the following the resistance decreases with rise in temperature? |
| A. | LDR |
| B. | NTC thermistors |
| C. | Nichrome conductors |
| D. | ACSR conductors |
| Answer» E. | |
| 1741. |
In MKS system one Kilowatt is equal to |
| A. | 1.36 HP |
| B. | 1.34 HP |
| C. | 1.5HP |
| D. | 1.6HP |
| Answer» D. 1.6HP | |
| 1742. |
A light dependent resistors is basically a: |
| A. | power resistor |
| B. | non-metallic resistor |
| C. | carbon resistor |
| D. | variable resistor |
| Answer» C. carbon resistor | |
| 1743. |
Electric flux at a point in an electric field is |
| A. | positive |
| B. | negative |
| C. | zero |
| D. | none of these |
| Answer» E. | |
| 1744. |
The element of electric heater is made of: |
| A. | copper |
| B. | carbon |
| C. | steel |
| D. | nichrome |
| Answer» E. | |
| 1745. |
Ohm's law is not applicable to: |
| A. | D. c. circuits |
| B. | High currents |
| C. | Small resistors |
| D. | Semiconductors |
| Answer» E. | |
| 1746. |
Filaments of electric bulbs are usually made of: |
| A. | nichrome |
| B. | carbon |
| C. | tungsten |
| D. | copper |
| Answer» D. copper | |
| 1747. |
Krichoffs current laws is applicable to only: |
| A. | closed loops in a network |
| B. | electronic circuits |
| C. | junctions in a network |
| D. | electric circuits |
| Answer» E. | |
| 1748. |
Specific resistance of a substance is measured in: |
| A. | ohm/m |
| B. | m/ohm |
| C. | mho/m |
| D. | mho |
| Answer» D. mho | |
| 1749. |
With increase in temperature, the resistance of copper: |
| A. | decreases |
| B. | increases |
| C. | becomes zero |
| D. | remains constant |
| Answer» E. | |
| 1750. |
Specific resistance of a conductor depends upon: |
| A. | composition of the conductor |
| B. | length of the conductor |
| C. | area of cross-section of the conductor |
| D. | resistance of the conductor |
| Answer» B. length of the conductor | |