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EEE :: Electrical Engineering Materials

  1. __________ is the main constituent of glass

  2. A.

     Fe203

    B.

     Si02

    C.

     AI2O3

    D.

     B2O3


  3. In a superconductor the value of critical density depends upon

  4. A.

     Magnetic field strength

    B.

     Temperature

    C.

     Either A or B

    D.

     Both A and B


  5. The co-ordination number of a simple cubic structure is

  6. A.

     2

    B.

     4

    C.

     6

    D.

     8


  7. The conduction of electricity, in semiconductors, takes place due to movement of

  8. A.

     Positive ions only

    B.

     Negative ions only

    C.

     Positive and negative ions

    D.

     Electrons and holes


  9. In conductors conduction of electricity takes place due to movement of

  10. A.

     Electrons only

    B.

     Positive ions only

    C.

     Negative ions only

    D.

     Positive and negative ions


  11. A highly conductive material must have

  12. A.

     Highest conductivity

    B.

     Lowest temperature co-efficient

    C.

     Good mechanical strength

    D.

     Good corrosion resistance

    E.

     All of the above


  13. Is an element used in semiconductors whose atoms have three valence electrons.

  14. A.

     An acceptor

    B.

     A donor

    C.

     Germanium

    D.

     Silicon


  15. The coils of D.C. motor starter are wound with wire of

  16. A.

     Copper

    B.

     Kanthal

    C.

     Manganin

    D.

     Nichrome


  17. Due to which of the following factors the brush wear rate is altered?

  18. A.

     Speed of the machine

    B.

     Contact pressure

    C.

     Surface conditions of brush and commutator

    D.

     All of the above


  19. Which of the following affect greatly the resistivity of electrical conductors?

  20. A.

     Composition

    B.

     Pressure

    C.

     Size

    D.

     Temperature