AFCAT: Electronics MCQs (Practice_Test 10 of 13)

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  1. The breakdown mechanism in a lightly doped p-n junction under reverse biased condition is called

    1. avalanche breakdown

    2. zener breakdown

    3. breakdown by tunnelling

    4. high voltage breakdown

    Answer: a

  2. For a large values of |VDS|, a FET behave as

    1. Voltage controlled resistor

    2. Current controlled current source

    3. Voltage controlled current source

    4. Current controlled resistor

    Answer: c

  3. In a full wave rectifier without filter, the ripple factor is

    1. 0.482

    2. 1.21

    3. 1.79

    4. 2.05

    Answer: a

  4. Space charge region around a P-N junction

    1. does not contain mobile carries

    2. contains both free electrons and holes

    3. contains one type of mobile carriers depending on the level of doping of the P or N regions

    4. contains electrons only as free carriers

    Answer: a

  5. In a JFET, at pinch-off voltage applied on the gate

    1. The drain current becomes almost zero

    2. The drain current begins to decrease

    3. The drain current is almost at saturation value

    4. The drain to source voltage is close to zero volts

    Answer: c

  6. The value of ripple factor of a half wave rectifier without filter is approximately

    1. 1.2

    2. o. 2

    3. 2.2

    4. 2.0

    Answer: a

  7. In an intrinsic semiconductor, the Fermi-level is

    1. closer to the valence band

    2. midway between conduction and valence band

    3. closer to the conduction band

    4. within the valence band

    Answer: c

  8. The transformer utilization factor of a half wave rectifier is approximately

    1. 0.6

    2. 0.3

    3. 0.9

    4. 1.1

    Answer: b

  9. Transistor is a

    1. Current controlled current device

    2. Current controlled voltage device

    3. Voltage controlled current device

    4. Voltage controlled voltage device

    Answer: a

  10. If the output voltage of a bridge rectifier is 100V, the PIV of diode will be

    1. 100 * Square root (2) V

    2. 200/(pi) V

    3. 100 * (pi) V

    4. 100/2 V

    Answer: d