In the name of ALLAH, the most beneficient, the most merciful

Circuit Theory (PHY301)

Multiple Choice Questions (MCQs)

Objective Questions

  1. For a P-N junction under forward bias

    1. more forward current flows
    2. no forward current flows
    3. more reverse current flows
    4. infinite reverse current flows
  2. Diode small signal resistance rd at bias current of 5mA for n = 1 will be

    1. 10 ohms
    2. 8 ohms
    3. 5 ohms
    4. 2.5 ohms
  3. True or false, hole current is opposit of electron current?

    1. True
    2. False
  4. The width of the depletion layer of a junction

    1. decreases with light doping
    2. increases with heavy doping
    3. under reverse bias
    4. is increased under reverse bias
  5. A transformer may consists of ________.

    1. one winding
    2. two windings
    3. two or more than two windings
    4. no winding
  6. If 10w of power is applied to primary of an ideal transformer with a turn ratio of 5, the power delivered to the secondary load is

    1. 25w
    2. 50w
    3. 0.5
    4. 10w
  7. The primary and secondary winding of transformer are

    1. physically touched
    2. physically isolated
    3. touched with conductor
    4. largely separated
  8. In an N-type semiconductor material, the majority carrier are

    1. holes
    2. electron
    3. ions
    4. protons
  9. Using exponential model for a diode that conducts at 1mA with n = 2, the change in current due to change of voltage by 5mv will be

    1. 0.4mA
    2. 0.8mA
    3. 3mA
    4. 0.11mA
  10. A transformer will be out of phase when ________.

    1. output voltage is 0 degree out of phase with input voltage
    2. output voltage is 180 degree out of phase with input voltage
    3. output voltage is 360 degree out of phase with input voltage
    4. output voltage is same as input voltage
  11. In a P- type semiconductor material, the majority carriers are ________.

    1. Holes
    2. Electrons
    3. Ions
    4. Protons
  12. When the turn ratio of a transformer is 10 and primary ac voltage is 6v, the secondary voltage is ________.

    1. 36v
    2. 6v
    3. 60v
    4. 0.6v
  13. If turn ratio of a transformer is 5 and secondary current is 2A, the primary current is ________.

    1. 2.5A
    2. 10A
    3. 0.4A
    4. 7A
  14. Analysing the farward biase region of junction diode , the value of constant voltage,VT is ________.

    1. 25.02V
    2. 10mV
    3. 25.02mV
    4. 5Mv
  15. Secondary voltage is greater in magnitude as compared to primary voltage in a ________.

    1. step down transformer
    2. step up transformer
    3. isolated transformer
    4. simple transformer
  16. If a silicon diode conducts at 2mA and whose n = 1, the slope of diode will be at

    1. 1/25 ohms
    2. 1/2 ohms
    3. 2/25 ohms
    4. 2 ohms
  17. Addition of impuritirs in semiconductor material to produce more current is called

    1. intrinsic
    2. dopping
    3. bonding
    4. excitation
  18. There is a ________ energy gap between valence and conduction band.

    1. forbidden
    2. permitted
  19. Which transformer gives less voltage at secondary as compared to primary?

    1. islated transformer
    2. step up transformer
    3. step down transformer
    4. all transformer
  20. There is no voltage drop across diode when forward biased, in case of

    1. ideal diode model
    2. practical diode model