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ECE :: Electronic Devices and Circuits

  1. Voltage series feedback (Also called series-shunt feedback) results in

  2. A.
    increase in both I/P and O/P impedances
    B.
    decrease in both I/P and O/P impedances
    C.
    increase in I/P impedance and decrease in O/P impedance
    D.
    decrease in I/P impedance and increase in O/P impedance

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  3. How many free electrons does a p type semiconductor has?

  4. A.
    only those produced by thermal energy
    B.
    only those produced by doping
    C.
    those produced by doping as well as thermal energy
    D.
    any of the above

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  5. Which of the following has highest resistivity?

  6. A.
    Mica
    B.
    Paraffin wax
    C.
    Air
    D.
    Mineral oil

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  7. Assertion (A): In p-n-p transistor collector current is termed negative.

    Reason (R): In p-n-p transistor holes are majority carriers.

  8. 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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  9. The sensitivity of human eyes is maximum at

  10. A.
    white portion of spectrum
    B.
    green portion of spectrum
    C.
    red portion of spectrum
    D.
    violet portion of spectrum

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  11. In a bipolar transistor, the base collector junction has

  12. A.
    forward bias
    B.
    reverse bias
    C.
    zero bias
    D.
    zero or forward bias

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  13. An intrinsic silicon sample has 1 million free electrons at room temperature. As the temperature is increased

  14. A.
    the number of free electrons increases
    B.
    the number of free electrons increases but the number of holes decreases
    C.
    the number of free electrons and holes increase by the same amount
    D.
    the number of free electrons and holes increase but not by the same amount

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  15. What is the necessary a.c. input power from the transformer secondary used in a half wave rectifier to deliver 500 W of d.c. power to the load?

  16. A.
    1232 W
    B.
    848 W
    C.
    616 W
    D.
    308 W

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  17. In a semi-conductor diode, the barrier offers opposition to

  18. A.
    holes in P-region only
    B.
    free electrons in N-region only
    C.
    majority carriers in both regions
    D.
    majority as well as minority carriers in both regions

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  19. In a half wave rectifier, the load current flows

  20. A.
    only for the positive half cycle of the input signal
    B.
    only for the negative half cycle of the input signal
    C.
    for full cycle
    D.
    for less than fourth cycle

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