Quiz  /  Cables Electrical Engineering MCQ Interview Questions and Answers PDF

  • 1. 
    The insulating material for a cable should have

  • low cost
  • high dielectric strength
  • high mechanical strength
  • all of the above

  • 2. 
    Which of the following protects a cable against mechanical injury ?

  • Bedding
  • Sheath
  • Armouring
  • None of the above

  • 3. 
    Which of the following insulation is used in cables ?

  • Varnished cambric
  • Rubber
  • Paper
  • Any of the above

  • 4. 
    Empire tape is

  • varnished cambric
  • vulcanised rubber
  • impregnated paper
  • none of the above

  • 5. 
    The thickness of the layer of insulation on the conductor, in cables, depends upon

  • reactive power
  • power factor
  • voltage
  • current carrying capacity

  • 6. 
    The bedding on a cable consists of

  • hessian cloth
  • jute
  • any of the above
  • none of the above

  • 7. 
    The insulating material for cables should

  • be acid proof
  • be non-inflammable
  • be non-hygroscopic
  • have all above properties

  • 8. 
    In a cable immediately above metallic sheath _____ is provided.

  • earthing connection
  • bedding
  • armouring
  • none of the above

  • 9. 
    The current carrying capacity of cables in D.C. is more thanthat in A.C. mainly due to

  • absence of harmonics
  • non-existence of any stability limit
  • smaller dielectric loss
  • absence of ripples
  • none of the above

  • 10. 
    In case of three core flexible cable the colour of the neutral is

  • blue
  • black
  • brown
  • none of the above

  • 11. 
    cables are used for 132 kV lines.

  • High tension
  • Super tension
  • Extra high tension
  • Extra super voltage

  • 12. 
    Conduit pipes are normally used to protect _____ cables.

  • unsheathed cables
  • armoured
  • PVC sheathed cables
  • all of the above

  • 13. 
    The minimum dielectric stress in a cable is at

  • armour
  • bedding
  • conductor surface
  • lead sheath

  • 14. 
    In single core cables armouring is not done to

  • avoid excessive sheath losses
  • make it flexible
  • either of the above
  • none of the above

  • 15. 
    Dielectric strength of rubber is around

  • 5 kV/mm
  • 15 kV/mm
  • 30 kV/mm
  • 200 kV/mm

  • 16. 
    Low tension cables are generally used up to

  • 200 V
  • 500 V
  • 700 V
  • 1000 V

  • 17. 
    In a cable, the maximum stress under operating conditions is at

  • insulation layer
  • sheath
  • armour
  • conductor surface

  • 18. 
    High tension cables are generally used up to

  • 11kV
  • 33kV
  • 66 kV
  • 132 kV

  • 19. 
    The surge resistance of cable is

  • 5 ohms
  • 20 ohms
  • 50 ohms
  • 100 ohms

  • 20. 
    PVC stands for

  • polyvinyl chloride
  • post varnish conductor
  • pressed and varnished cloth
  • positive voltage conductor
  • none of the above

  • 21. 
    the cables, the location of fault is usually found out by comparing

  • the resistance of the conductor
  • the inductance of conductors
  • the capacitances of insulated conductors
  • all above parameters

  • 22. 
    In capacitance grading of cables we use a ______ dielectric.

  • composite
  • porous
  • homogeneous
  • hygroscopic

  • 23. 
    Pressure cables are generally not used beyond

  • 11 kV
  • 33 kV
  • 66 kV
  • 132 kV

  • 24. 
    The material for armouring on cable is usually

  • steel tape
  • galvanised steel wire
  • any of the above
  • none of the above

  • 25. 
    Cables, generally used beyond 66 kV are

  • oil filled
  • S.L. type
  • belted
  • armoured

  • 26. 
    The relative permittivity of rubber is

  • between 2 and 3
  • between 5 and 6
  • between 8 and 10
  • between 12 and 14

  • 27. 
    Solid type cables are considered unreliable beyond 66 kV because

  • insulation may melt due to higher temperature
  • skin effect dominates on the conductor
  • of corona loss between conductor and sheath material
  • there is a danger of breakdown of insulation due to the presence of voids

  • 28. 
    If the length of a cable is doubled, its capacitance

  • becomes one-fourth
  • becomes one-half
  • becomes double
  • remains unchanged

  • 29. 
    In cables the charging current

  • lags the voltage by 90°
  • leads the voltage by 90°
  • lags the voltage by 180°
  • leads the voltage by 180°

  • 30. 
    If a cable of homogeneous insulation has a maximum stress of 10 kV/mm, then the dielectric strength of insulation should be

  • 5 kV/mm
  • 10 kV/mm
  • 15 kV/mm
  • 30 kV/mm

  • 31. 
    In the cables, sheaths are used to

  • prevent the moisture from entering the cable
  • provide enough strength
  • provide proper insulation
  • none of the above

  • 32. 
    The intersheaths in the cables are used to

  • minimize the stress
  • avoid the requirement of good insulation
  • provide proper stress distribution
  • none of the above

  • 33. 
    The electrostatic stress in underground cables is

  • same at the conductor and the sheath
  • minimum at the conductor and maximum at the sheath
  • maximum at the conductor and minimum at the sheath
  • zero at the conductor as well as on the sheath
  • none of the above

  • 34. 
    The breakdown of insulation of the cable can be avoided economically by the use of

  • inter-sheaths
  • insulating materials with different dielectric constants
  • both (a) and (b)
  • none of the above

  • 35. 
    The insulation of the cable decreases with

  • the increase in length of the insulation
  • the decrease in the length of the insulation
  • either (a) or (b)
  • none of the above

  • 36. 
    A cable carrying alternating current has

  • hysteresis losses only
  • hysteresis and leakage losses only
  • hysteresis, leakage and copper losses only
  • hysteresis, leakage, copper and friction losses

  • 37. 
    Capacitance grading of cable implies

  • use of dielectrics of different permeabilities
  • grading according to capacitance of cables per km length
  • cables using single dielectric in different concentrations
  • capacitance required to be introduced at different lengths to counter the effect of inductance
  • none of the above

  • 38. 
    Underground cables are laid at sufficient depth

  • to minimise temperature stresses
  • to avoid being unearthed easily due to removal of soil
  • to minimise the effect of shocks and vibrations due to gassing vehicles, etc.
  • for all of the above reasons

  • 39. 
    The advantage of cables over overhead transmission lines is

  • easy maintenance
  • low cost
  • can be used in congested areas
  • can be used in high voltage circuits

  • 40. 
    The thickness of metallic shielding on cables is usually

  • 0.04 mm
  • 0.2 to 0.4 mm
  • 3 to 5 mm
  • 40 to 60 mm

  • 41. 
    Cables for 220 kV lines are invariably

  • mica insulated
  • paper insulated
  • compressed oil or compressed gas insulated
  • rubber insulated
  • none of the above

  • 42. 
    Is a cable is to be designed for use on 1000 kV, which insulation would you prefer ?

  • Polyvinyle chloride
  • Vulcanised rubber
  • Impregnated paper
  • Compressed SFe gas
  • none of the above

  • 43. 
    If a power cable and a communication cable are to run parallel the minimum distance between the two, to avoid interference, should be

  • 2 cm
  • 10 cm
  • 50 cm
  • 400 cm

  • 44. 
    Copper as conductor for cables is used as

  • annealed
  • hardened and tempered
  • hard drawn
  • alloy with chromium

  • 45. 
    The insulating material should have

  • low permittivity
  • high resistivity
  • high dielectric strength
  • all of the above

  • 46. 
    The advantage of oil filled cables is

  • more perfect impregnation
  • smaller overall size
  • no ionisation, oxidation and formation of voids
  • all of the above

  • 47. 
    The breakdown voltage of a cable depends on

  • presence of moisture
  • working temperature
  • time of application of the voltage
  • all of the above
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