MCQOPTIONS
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MCQOPTIONS
This section includes 234 Mcqs, each offering curated multiple-choice questions to sharpen your Electrical Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
The breakdown voltage of a cable depends on |
| A. | presence of moisture |
| B. | working temperature |
| C. | time of application of the voltage |
| D. | all of the above |
| Answer» E. | |
| 2. |
The disadvantage with paper as insulating material is |
| A. | it is hygroscopic |
| B. | it has high capacitance |
| C. | it is an organic material |
| D. | none of the above |
| Answer» B. it has high capacitance | |
| 3. |
The advantage of oil filled cables is |
| A. | more perfect impregnation |
| B. | smaller overall size |
| C. | no ionisation, oxidation and formation of voids |
| D. | all of the above |
| Answer» E. | |
| 4. |
The insulating material should have |
| A. | low permittivity |
| B. | high resistivity |
| C. | high dielectric strength |
| D. | all of the above |
| Answer» E. | |
| 5. |
Copper as conductor for cables is used as |
| A. | annealed |
| B. | hardened and tempered |
| C. | hard drawn |
| D. | alloy with chromium |
| Answer» B. hardened and tempered | |
| 6. |
If a power cable and a communication cable are to run parallel the minimum distance between the two, to avoid interference, should be |
| A. | 2 cm |
| B. | 10 cm |
| C. | 50 cm |
| D. | 400 cm |
| Answer» D. 400 cm | |
| 7. |
Is a cable is to be designed for use on 1000 kV, which insulation would you prefer ? |
| A. | Polyvinyle chloride |
| B. | Vulcanised rubber |
| C. | Impregnated paper |
| D. | Compressed SFe gas |
| Answer» E. | |
| 8. |
Cables for 220 kV lines are invariably |
| A. | mica insulated |
| B. | paper insulated |
| C. | compressed oil or compressed gas insulated |
| D. | rubber insulated |
| Answer» D. rubber insulated | |
| 9. |
The thickness of metallic shielding on cables is usually |
| A. | 0.04 mm |
| B. | 0.2 to 0.4 mm |
| C. | 3 to 5 mm |
| D. | 40 to 60 mm |
| Answer» B. 0.2 to 0.4 mm | |
| 10. |
The current due to electron flow in conduction band is the hole current in valence band. |
| A. | equal to |
| B. | less than |
| C. | greater than |
| D. | any of the above |
| Answer» D. any of the above | |
| 11. |
The conductivity of an extrinsic semiconductor with temperature |
| A. | decreases |
| B. | remains constant |
| Answer» C. | |
| 12. |
For a particular material the Hall coefficient was found to be zero. The material is |
| A. | insulator |
| B. | metal |
| C. | intrinsic semiconductor |
| D. | none of the above |
| Answer» C. intrinsic semiconductor | |
| 13. |
The carbon percentage is least in |
| A. | low carbon steel |
| B. | wrought iron |
| C. | cast iron |
| D. | malleable iron |
| Answer» C. cast iron | |
| 14. |
In conductors conduction of electricity takes place due to movement of |
| A. | electrons only |
| B. | positive ions only |
| C. | negative ions only |
| D. | none of the above |
| Answer» B. positive ions only | |
| 15. |
Superconducting metal in super conducting state has relative permeability of |
| A. | zero |
| B. | one |
| C. | negative |
| D. | more than one |
| Answer» B. one | |
| 16. |
Surface resistance of an insulating material is reduced due to the |
| A. | smoky and dirty atmosphere` |
| B. | humidity in the atmosphere |
| C. | both (a) and (b) |
| D. | neither (a) nor (b) |
| Answer» D. neither (a) nor (b) | |
| 17. |
Effect of moisture on the insulating materials is to |
| A. | decrease dielectric constant |
| B. | decrease dielectric strength |
| C. | decrease insulation resistance |
| D. | all of the above |
| Answer» E. | |
| 18. |
Which of the following factors affect resistivity of metals |
| A. | Age hardening |
| B. | Alloying |
| C. | Temperature |
| D. | All of the above |
| Answer» E. | |
| 19. |
The forbidden gap in an insulator is |
| A. | large |
| B. | small |
| C. | nil |
| D. | any of the above |
| Answer» B. small | |
| 20. |
Spark plug makes use of which of the following materials for insulation ? |
| A. | Porcelain |
| B. | Slate |
| C. | Asbestos |
| D. | Glass |
| Answer» B. Slate | |
| 21. |
If the resistance of a conductor does not vary in accordance with Ohm’s law it is known as |
| A. | non-linear conductor |
| B. | reverse conductor |
| C. | bad-conductor |
| D. | non-conductor |
| Answer» B. reverse conductor | |
| 22. |
The photo-electric effect occurs only when the incident light has more than a certain critical |
| A. | intensity |
| B. | speed |
| C. | frequency |
| D. | wave length |
| Answer» D. wave length | |
| 23. |
________ has the best damping properties. |
| A. | Diamond |
| B. | High speed steel |
| C. | Mild steel |
| D. | Cast iron |
| Answer» E. | |
| 24. |
Selenium is _____ semiconductor` |
| A. | extrnisic |
| B. | intmisic |
| C. | N-type |
| D. | P-type |
| Answer» C. N-type | |
| 25. |
Which of the following is a semiconductor material ? |
| A. | Phosphorous |
| B. | Rubber |
| C. | Silicon |
| D. | Aluminium |
| Answer» D. Aluminium | |
| 26. |
The conduction of electricity, in semiconductors, takes place due to movement of |
| A. | positive ions only |
| B. | negative ions only |
| C. | positive and negative ions |
| D. | electrons and holes |
| Answer» E. | |
| 27. |
Due to which of the following fact, in India, aluminium is replacing copper ? |
| A. | Aluminium is more ductile and malleable than coppe |
| B. | Aluminium is available in plenty, cheaper and lighter than copper |
| C. | Aluminium has lower resistivity than that of copper |
| D. | Aluminium has less temperature co-efficient than copper |
| Answer» C. Aluminium has lower resistivity than that of copper | |
| 28. |
Thermocouples are mainly used for the measurement of |
| A. | temperature |
| B. | resistance |
| C. | eddy currents |
| D. | coupling co-efficient |
| Answer» B. resistance | |
| 29. |
is the property of absorbing moisture from atmosphere. |
| A. | Solubility |
| B. | Viscosity |
| C. | Porosity |
| D. | Hygroscopicity |
| Answer» E. | |
| 30. |
Which of the following materials is the best conductor of electricity? |
| A. | Tungsten |
| B. | Aluminium |
| C. | Copper |
| D. | Carbon |
| Answer» D. Carbon | |
| 31. |
Substances whose specific resistance abruptly decreases at very low temperature are called |
| A. | insulators |
| B. | conductors |
| C. | semiconductors |
| D. | superconductors |
| Answer» E. | |
| 32. |
Which of the following materials is used for making coils of standard resistances ? |
| A. | Copper |
| B. | Nichrome |
| C. | Platinum |
| D. | Manganin |
| Answer» E. | |
| 33. |
Copper, even though costly, finds use in the windings of electrical machines because |
| A. | copper points offer low contact resistance |
| B. | copper can be easily soldered and welded |
| C. | copper windings are less bulky and the machines become compact |
| D. | all of the above |
| Answer» E. | |
| 34. |
Due to which of the following reasons copper and aluminium are not used for heating elements ? |
| A. | Both have great tendency for oxidation ( |
| B. | Both have low melting point |
| C. | Very large length of wires will be required |
| D. | All of the above |
| Answer» E. | |
| 35. |
Which of the following is an advantage of stranded conductor over equivalent single conductor ? |
| A. | Less liability to kink |
| B. | Greater flexibility |
| C. | Less liability to break |
| D. | All of the above |
| Answer» E. | |
| 36. |
Platinum is used in |
| A. | electrical contacts |
| B. | thermocouple |
| C. | heating element in high temperature furnace |
| D. | all of the above |
| Answer» E. | |
| 37. |
Low resistivity materials are used in |
| A. | transformer, motor and generator windings |
| B. | transmission and distribution lines |
| C. | house wiring |
| D. | all above applications |
| Answer» E. | |
| 38. |
Steel wire is used as |
| A. | overhead telephone wire |
| B. | earth wire |
| C. | core wire of ACSR |
| D. | all of the above |
| Answer» E. | |
| 39. |
Which of the following high resistance materials has the highest operating temperature ? |
| A. | Kanthal |
| B. | Manganin |
| C. | Nichrome |
| D. | Eureka |
| Answer» B. Manganin | |
| 40. |
Carbon bearings are used under which of the following conditions ? |
| A. | Where lubrication is difficult or im-possible |
| B. | Where corrosive chemical action exists |
| C. | Where high temperature exists |
| D. | All of the above |
| Answer» E. | |
| 41. |
Which of the following are non-conductors of electricity? |
| A. | Non-metal solids except carbon |
| B. | Air and most other gases |
| C. | Pure water and liquids in general except mercury |
| D. | All of the above |
| Answer» E. | |
| 42. |
Due to which of the following factors the brush wear rate is altered? |
| A. | Speed of the machine |
| B. | Contact pressure |
| C. | Surface conditions of brush and commutator |
| D. | All of the above |
| Answer» E. | |
| 43. |
Carbon rods are used in wet and dry cells because |
| A. | carbon rod serves as conductor |
| B. | carbon can resist the attack of battery acid |
| C. | both (a) and (b) |
| D. | either (a) or (b) |
| Answer» D. either (a) or (b) | |
| 44. |
Carbon resistors are used extensively because they are |
| A. | easy to make |
| B. | compact |
| C. | inexpensive |
| D. | all of the above reasons |
| Answer» E. | |
| 45. |
Which of the following material is not a semiconductor ? |
| A. | Silica |
| B. | Germanium |
| C. | Selenium |
| D. | Gallium-arsenide |
| Answer» B. Germanium | |
| 46. |
The impurity atoms is semiconductors |
| A. | inject more charge carriers |
| B. | reduce the energy gap |
| C. | increase the kinetic energy of valence electrons |
| D. | all of the above |
| Answer» C. increase the kinetic energy of valence electrons | |
| 47. |
Due to which of the following reasons aluminium does not corrode in atmosphere ? |
| A. | Aluminium is a noble metal |
| B. | Atmospheric oxygen can only diffuse very slowly through the oxide layer which is formed on the surface of aluminium |
| Answer» C. | |
| 48. |
In a crystal, an atom vibrates at a frequency determined by |
| A. | the heat content of the crystal |
| B. | the stiffness of the bonds it makes with neighbors |
| Answer» C. | |
| 49. |
The resistivity of a metal is a function of temperature because |
| A. | the amplitude of vibration of the atoms varies with temperature |
| B. | the electron density varies with temperature |
| Answer» B. the electron density varies with temperature | |
| 50. |
The conductivity of a metal is determined by |
| A. | the electronic concentration and the mobility of the free electrons |
| B. | `the number of valence electrons per atom |
| C. | either (a) or (b) |
| D. | none of the above |
| Answer» B. `the number of valence electrons per atom | |