electrical engineering Mcqs
1. economics of power generation2. analog electronics3. solid state switching circuits4. parallel circuits5. switchgear and protection6. op amp circuits7. transistor audio power amplifiers8. electrostatics9. heating and welding10. multi stage transistor amplifiers11. passive filters12. network theorems13. regulated d c power supply14. a c fundamentals circuits and circuit theory15. electromagnetic induction16. power electronics17. magnetism and electromagnetism18. transformers19. modulation and demodulation20. d c generators21. semiconductor theory22. single phase induction motors23. semiconductor diode24. hybrid parameters25. digital electronics26. oscillators27. earthing or grounding28. single stage transistor amplifiers29. d c motors30. transistor biasing31. amplifiers with negative feedback32. basic electrical33. electronic instruments34. synchronous motors35. field effect transistors fet36. magnetic circuit37. control systems38. industrial drives39. power generation40. series parallel circuits41. transistor tuned amplifiers42. electrical engineering materials43. rectifiers and converters44. integrated circuits45. scr silicon controlled rectifiers46. cables47. polyphase induction motors48. measurement and instrumentation49. transistors50. electrical machine design51. electrolysis and storage of batteries52. electric traction53. transmission and distribution
6701. If a cable of homogeneous insulation has a maximum stress of 10 kV/mm, then the dielectric strength of insulation should be_______________?
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A. 15 kV/mm

B. 30 kV/mm

C. 10 kV/mm

D. 5 kV/mm

6702. Copper as conductor for cables is used as________?
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A. hard drawn

B. hardened and tempered

C. alloy with chromium

D. annealed
6703. The electrostatic stress in underground cables is_________?
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A. none of the above

B. same at the conductor and the sheath

C. maximum at the conductor and minimum at the sheath

D. zero at the conductor as well as on the sheath

E. minimum at the conductor and maximum at the sheath

6704. In congested areas where excavation is expensive and inconvenient draw in system of laying of underground cables is often adopted
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A. Yes

B. No

6705. In the cables, sheaths are used to___________?
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A. provide enough strength

B. none of the above

C. prevent the moisture from entering the cable

D. provide proper insulation

6706. PVC stands for____________?
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A. positive voltage conductor

B. pressed and varnished cloth

C. post varnish conductor

D. polyvinyl chloride

E. none of the above

6707. The advantage of oil filled cables is_________?
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A. more perfect impregnation

B. smaller overall size

C. all of the above

D. no ionisation, oxidation and formation of voids

6708. Conduit pipes are normally used to protect _______ cables
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A. PVC sheathed cables

B. all of the above

C. unsheathed cables

D. armoured

6709. In capacitance grading a homogeneous dielectric is used
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A. Yes

B. No
6710. The material for armouring on cable is usually__________?
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A. any of the above

B. none of the above

C. galvanised steel wire

D. steel tape

6711. Which of the following protects a cable against mechanical injury___________?
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A. Armouring

B. Bedding

C. None of the above

D. Sheath

6712. The surge resistance of cable is__________?
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A. 100 ohms

B. 50 ohms

C. 5 ohms

D. 20 ohms

6713. A cable carrying alternating current has__________?
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A. hysteresis, leakage, copper and friction losses

B. hysteresis losses only

C. hysteresis and leakage losses only

D. hysteresis, leakage and copper losses only

6714. Pressure cables are generally not used beyond__________?
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A. 66 kV

B. 33 kV

C. 132 kV

D. 11 kV

6715. The breakdown of insulation of the cable can be avoided economically by the use of___________?
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A. inter-sheaths

B. insulating materials with different dielectric constants

C. both (A) and (B)

D. none of the above

6716. The minimum dielectric stress in a cable is at_____________?
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A. conductor surface

B. bedding

C. lead sheath

D. armour

6717. Solid type cables are considered unreliable beyond 66 kV because___________?
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A. skin effect dominates on the conductor

B. there is a danger of breakdown of insulation due to the presence of voids

C. of corona loss between conductor and sheath material

D. insulation may melt due to higher temperature

6718. The thickness of metallic shielding on cables is usually_______________?
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A. 0.04 mm

B. 3 to 5 mm

C. 40 to 60 mm

D. 0.2 to 0.4 mm

6719. Is a cable is to be designed for use on 1000 kV, which insulation would you prefer ____________?
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A. Compressed SFe gas

B. Polyvinyle chloride

C. Impregnated paper

D. none of the above

E. Vulcanised rubber

6720. The current carrying capacity of cables in D.C. is more than that in A.C. mainly due to__________?
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A. absence of harmonics

B. none of the above

C. non-existence of any stability limit

D. absence of ripples

E. smaller dielectric loss
6721. Natural rubber is obtained from milky sap of tropical trees
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A. Yes

B. No

6722. The metallic sheath may be made of lead or lead alloy or of aluminium ?
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A. Yes

B. No
6723. Cables for 220 kV lines are invariably____________?
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A. none of the above

B. rubber insulated

C. compressed oil or compressed gas insulated

D. mica insulated

E. paper insulated

6724. The thickness of the layer of insulation on the conductor, in cables, depends upon___________?
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A. voltage

B. reactive power

C. power factor

D. current carrying capacity

6725. The intersheaths in the cables are used to_____________?
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A. avoid the requirement of good insulation

B. provide proper stress distribution

C. none of the above

D. minimize the stress

6726. In the cables, the location of fault is usually found out by comparing____________?
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A. the resistance of the conductor

B. the capacitances of insulated conductors

C. all above parameters

D. the inductance of conductors

6727. Low tension cables are generally used up to___________?
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A. 500 V

B. 1000 V

C. 700 V

D. 200 V

6728. The advantage of cables over overhead transmission lines is___________?
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A. can be used in congested areas

B. can be used in high voltage circuits

C. low cost

D. easy maintenance

6729. The bedding on a cable consists of____________?
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A. none of the above

B. any of the above

C. jute

D. hessian cloth

6730. In a cable, the maximum stress under operating conditions is at___________?
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A. insulation layer

B. armour

C. sheath

D. conductor surface
6731. If a power cable and a communication cable are to run parallel the minimum distance between the two, to avoid interference, should be______________?
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A. 400 cm

B. 50 cm

C. 10 cm

D. 2 cm

6732. In a cable immediately above metallic sheath ______ is provided
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A. none of the above

B. armouring

C. earthing connection

D. bedding
6733. In a cable the voltage stress is maximum at____________?
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A. sheath

B. insulator

C. core of the conductor

D. surface of the conductor

6734. The insulation of the cable decreases with__________?
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A. the decrease in the length of the insulation

B. either A. or (b)

C. the increase in length of the insulation

D. none of the above

6735. The insulating material for a cable should have__________?
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A. low cost

B. high dielectric strength

C. high mechanical strength

D. all of the above
6736. High tension cables are generally used up to_____________?
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A. 132 kV

B. 11kV

C. 66 kV

D. 33kV

6737. A certain cable has an insulation of relative permittivity 4. If the insulation is replaced by one of relative permittivity 2, the capacitance of the cable will become_____________?
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A. double

B. none of the above

C. four times

D. one half
6738. In capacitance grading of cables we use a _______ dielectric?
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A. homogeneous

B. hygroscopic

C. composite

D. porous

6739. Dielectric strength of rubber is around____________?
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A. 5 kV/mm

B. 30 kV/mm

C. 15 kV/mm

D. 200 kV/mm

6740. Capacitance grading of cable implies__________?
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A. use of dielectrics of different permeabilities

B. cables using single dielectric in different concentrations

C. capacitance required to be introduced at different lengths to counter the effect of inductance

D. none of the above

E. grading according to capacitance of cables per km length

6741. In case the air gap in an induction motor is increased____________?
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A. speed of motor will increase

B. the magnetising current of the rotor will decrease

C. the windage losses will increase

D. the power factor will decrease
6742. The stating torque of the slip ring induction motor can be increased by adding__________?
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A. external inductance to the rotor

B. external resistance to the rotor

C. external capacitance to the rotor

D. both resistance and inductance to rotor

6743. The starting torque of a squirrel-cage induction motor is___________?
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A. negligible

B. slightly more than full-load torque

C. same as full-load torque

D. low
6744. If any two phases for an induction motor are interchanged_______?
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A. the motor will run in reverse direction

B. the motor will burn

C. the motor will not run

D. the motor will run at reduced speed

6745. A change of 4% of supply voltage to an induction motor will produce a change of approximately ________?
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A. 4% in the rotor torque

B. 12% in the rotor torque

C. 8% in the rotor torque

D. 16% in the rotor torque
6746. In an induction motor, no-load the slip is generally____________?
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A. less than 1%

B. 1.50%

C. 4%

D. 2%

6747. The speed characteristics of an induction motor closely resemble the speedload characteristics of which of the following machines?
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A. none of the above

B. universal motor

C. D.C. shunt motor

D. D.C. series motor

6748. An induction motor can run at synchronous speed when____________?
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A. it is run on voltage higher than the rated voltage

B. it is run on load

C. it is run in reverse direction

D. e.m.f. is injected in the rotor circuit
6749. Which of the following component is usually fabricated out of silicon steel ?
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A. None of the above

B. Statorcore

C. Shaft

D. Bearings

6750. The maximum torque in an induction motor depends on___________?
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A. square of supply voltage

B. rotor inductive reactance

C. frequency

D. all of the above