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ECE :: Electronic Devices and Circuits

  1. Assertion (A): The forward resistance of a p-n diode is not constant.

    Reason (R): The v-i characteristics of p-n diode is non-linear.

  2. A.
    Both A and R are true and R is correct explanation of A
    B.
    Both A and R are true but R is not a correct explanation of A
    C.
    A is true but R is false
    D.
    A is false but R is true

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  3. For a photoengraving the mask used is

  4. A.
    master mask
    B.
    slave mask
    C.
    working mask
    D.
    photo mask

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  5. In a varactor diode the increase in width of depletion layer results in

  6. A.
    decrease in capacitance
    B.
    increase in capacitance
    C.
    no change in capacitance
    D.
    either (a) or (b)

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  7. In given figure a silicon diode is carrying a constant current of 1 mA. When the temperature of the diode is 20°C, VD is found to be 700 mV. If the temperature rises to 40°C, VD becomes approximately equal to

  8. A.
    747 mV
    B.
    660 mV
    C.
    680 mV
    D.
    700 mV

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  9. The work function of a photo surface whose threshold wave length is 1200 A, will be

  10. A.
    0.103 eV
    B.
    0.673 eV
    C.
    1.03 eV
    D.
    1.27 eV

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  11. The diameter of an atom is

  12. A.
    10-6 metre
    B.
    10-10 metre
    C.
    10-15 metre
    D.
    10-21 metre

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  13. N-type silicon is obtained by doping silicon with

  14. A.
    germanium
    B.
    aluminium
    C.
    boron
    D.
    phosphorus

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  15. When a p-n junction is reverse biased

  16. A.
    holes and electrons move away from the junction
    B.
    holes and electrons move towards the junction
    C.
    holes move towards junction and electrons move away from junction
    D.
    holes move away from junction and electrons move towards junction

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  17. If a sample of germanium and a sample of Si have the impurity density and are kept at room temperature then

  18. A.
    both will have equal value of resistivity
    B.
    both will have equal -ve resistivity
    C.
    resistivity of germanium will be higher than that of silicon
    D.
    resistivity of Si will be higher than of germanium

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  19. When a large number of atoms are brought together to form a crystal

  20. A.
    the energy levels of inner shell electrons are affected appreciably by the presence of other neighbouring atoms.
    B.
    The energy levels of outer shell electrons are affected appreciably by the presence of other neighbouring atoms.
    C.
    the energy levels of both inner and outer shell electrons are affected appreciably by the presence of other neighbouring atoms.
    D.
    none of the above.

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