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EEE :: Electrical Cables

  1. A cable carrying alternating current has

  2. A.

     Hysteresis losses only

    B.

     Hysteresis and leakage losses only

    C.

     Hysteresis, leakage and copper losses only

    D.

     Hysteresis, leakage, copper and friction losses


  3. In congested areas where excavation is expensive and inconvenient 'draw in system' of laying of underground cables is often adopted.

  4. A.

     Yes

    B.

     No


  5. The minimum dielectric stress in a cable is at

  6. A.

     Armour

    B.

     Bedding

    C.

     Conductor surface

    D.

     Lead sheath


  7. The breakdown voltage of a cable depends on

  8. A.

     Presence of moisture

    B.

     Working temperature

    C.

     Time of application of the voltage

    D.

     All of the above


  9. High tension cables are generally used up to

  10. A.

     11 kV

    B.

     33 kV

    C.

     66 kV

    D.

     132 kV


  11. Low tension cables are generally used up to

  12. A.

     200 V

    B.

     500 V

    C.

     700 V

    D.

     1000 V


  13. 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

  14. A.

     One half

    B.

     Double

    C.

     Four times

    D.

     None of the above


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

  16. A.

     Inter-sheaths

    B.

     Insulating materials with different dielectric constants

    C.

     Both (A) and (B)

    D.

     None of the above


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

  18. A.

     Insulation layer

    B.

     Sheath

    C.

     Armour

    D.

     Conductor surface


  19. Capacitance grading of cable implies

  20. A.

     Use of dielectrics of different permeabilities

    B.

     Grading according to capacitance of cables per km length

    C.

     Cables using single dielectric in different concentrations

    D.

     Capacitance required to be introduced at different lengths to counter the effect of inductance