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ECE :: Electronic Devices and Circuits

  1. In n channel JFET, the gate voltage is made more negative

  2. A.
    the channel width will increase
    B.
    the channel width will decrease
    C.
    the channel width and drain current will decrease
    D.
    the channel width will decrease and drain current will increase

  3. Metals approach superconductivity conditions

  4. A.
    near absolute zero temperature
    B.
    near critical temperature
    C.
    at triple point
    D.
    under the conditions of high temperature and pressure

  5. The phenomenon known as "Early effect" in a BJT refers to a reduction of the effective base width caused by

  6. A.
    electron-hole recombination at the base
    B.
    reverse biasing of the base collector junction
    C.
    forward biasing of emitter base junction
    D.
    the early removal of stored base charge during saturation to cut off switching

  7. At absolute zero temperature a semiconductor behaves like

  8. A.
    an insulator
    B.
    a super conductor
    C.
    a good conductor
    D.
    a variable resistor

  9. In a 741 OP-amp, there is 20 dB/decade fall-off starting at a relatively low frequency. This is due to

  10. A.
    applied load
    B.
    internal compensation
    C.
    impedance of the source
    D.
    power dissipation in the chip

  11. Which of the following material can be used in cable shields?

  12. A.
    Copper
    B.
    Aluminium
    C.
    Cast iron
    D.
    Lead

  13. The charge of an electron is

  14. A.
    1.6 x 10-17 coulomb
    B.
    1.6 x 10-19 coulomb
    C.
    1.6 x 10-21 coulomb
    D.
    1.6 x 10-23 coulomb

  15. The on voltage and forward breakover voltage of an SCR depend on

  16. A.
    gate current alone
    B.
    band gap of semiconductor alone
    C.
    gate current and semiconductor band gap respectively
    D.
    semiconductor band gap and gate current respectively

  17. EG for silicon is 1.12 eV and that for germanium is 0.72 eV. Therefore, it can be concluded that

  18. A.
    the conductivity of silicon will be less than that of germanium at room temperature
    B.
    the conductivity of silicon will be more than that of germanium at room temperature
    C.
    the conductivity of two will be same at 60°C
    D.
    the conductivity of two will be same at 100°C

  19. Assertion (A): The resistivity of intrinsic semiconductor decreases with increase in temperature.

    Reason (R): The forbidden gap decreases with increase in temperature.

  20. 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