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  1. A carbon resistor contains

  2. A.

     Carbon crystals

    B.

     Solid carbon granules

    C.

     Pulverized coal

    D.

     Finely divided carbon black.


  3. Which of the following material is not a semiconductor ?

  4. A.

     Silica

    B.

     Germanium

    C.

     Selenium

    D.

     Gallium-arsenide


  5. Which of the following materials is preferred for transmitting electrical energy over long distance ?

  6. A.

     Copper

    B.

     Aluminium

    C.

     Steel reinforced copper

    D.

     Steel reinforced aluminium


  7. The forbidden gap in an insulator is

  8. A.

     Large

    B.

     Small

    C.

     Nil

    D.

     Any of the above


  9. Platinum is used in

  10. A.

     Electrical contacts

    B.

     Thermocouple

    C.

     Heating element in high temperature furnace

    D.

     Grids of special purpose vacuum tubes

    E.

     All of the above


  11. In a crystal, an atom vibrates at a frequency determined by

  12. A.

     The heat content of the crystal

    B.

     The temperature of the crystal

    C.

     The stiffness of the bonds it makes with neighbors

    D.

     All of the above


  13. Due to which of the following reasons copper and aluminium are not used for heating elements ?

  14. 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


  15. Thermocouples are mainly used for the measurement of

  16. A.

     Temperature

    B.

     Resistance

    C.

     Eddy currents

    D.

     Coupling co-efficient


  17. Which of the following high resistance materials has the highest operating temperature ?

  18. A.

     Kanthal

    B.

     Manganin

    C.

     Nichrome

    D.

     Eureka


  19. The transition temperature of mercury is

  20. A.

     18.0°K

    B.

     9.22°K

    C.

     4.12°K

    D.

     1.14’K