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  • Question
  • If aac for transistor is 0.98 then ?ac is equal to


  • Options
  • A. 51
  • B. 49
  • C. 47
  • D. 45

  • Correct Answer
  • 49 

    Explanation
    If aac for transistor is 0.98 then ?ac is equal to 51 49 47 45 ..

    Electronic Devices and Circuits problems


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    • 1. Which of the following is true as regards photo emission?

    • Options
    • A. Velocity of emitted electrons is dependent on light intensity
    • B. Rate of photo emission is inversely proportional to light intensity
    • C. Maximum velocity of electron increases with decreasing wave length
    • D. Both holes and electrons are produced
    • Discuss
    • 2. The most commonly used semiconductor material is

    • Options
    • A. silicon
    • B. germanium
    • C. mixture of silicon and germanium
    • D. none of the above
    • Discuss
    • 3. In a p type material the Fermi level is 0.3 eV above valence band. The concentration of acceptor atoms is increased. The new position of Fermi level is likely to be

    • Options
    • A. 0.5 eV above valence band
    • B. 0.28 eV above valence band
    • C. 0.1 eV above valence band
    • D. below the valence band
    • Discuss
    • 4. As compared to an ordinary semiconductor diode, a Schottky diode

    • Options
    • A. has higher reverse saturation current
    • B. has higher reverse saturation current and higher cut in voltage
    • C. has higher reverse saturation current and lower cut in voltage
    • D. has lower reverse saturation current and lower cut in voltage
    • Discuss
    • 5. The minority carrier life time and diffusion constant in a semiconductor material are respectively 100 microsecond and 100 cm2/sec. The diffusion length is

    • Options
    • A. 0.1 cm
    • B. 0.01 cm
    • C. 0.0141 cm
    • D. 1 cm
    • Discuss
    • 6. Calculate wave impedance for TE mode

    • Options
    • A. (377)?
    • B. 226 ?
    • C. ?
    • D. 629 ?
    • Discuss
    • 7. In a 100 turn coil, if the flux through each turn is (t3 - 2t)mWb, the magnitude of the induced emf in the coil at a time of 4 sec is

    • Options
    • A. 46 mV
    • B. 56 mV
    • C. 4.6 V
    • D. 5.6 V
    • Discuss
    • 8. Charge needed within a unit sphere centred at the origin for producing a potential field,

    • Options
    • A. 12 pc
    • B. 60 pc
    • C. 120 pc
    • D. 180 pc
    • Discuss
    • 9. A wave is propagated in a waveguide at frequency of 9 GHz and separation is 2 cm between walls Calculate group velocity for dominant mode.

    • Options
    • A. 1.8 x 108 m/sec
    • B. 5 x 108 m/sec
    • C. 3 x 108 m/sec
    • D. 1.5 x 108 m/sec
    • Discuss
    • 10. A hollow rectangular waveguide has dimensions a = 2b. Calculate the amount of attenuation, if the frequency is 3 GHz, and b = 1 cm.

    • Options
    • A. 49
    • B. 47.33
    • C. 50.33
    • D. 50
    • Discuss


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