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

Circuit Theory (PHY301)

Multiple Choice Questions (MCQs)

Objective Questions

  1. 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
  2. True or false, hole current is opposit of electron current?

    1. True
    2. False
  3. The primary and secondary winding of transformer are

    1. physically touched
    2. physically isolated
    3. touched with conductor
    4. largely separated
  4. 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
  5. 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
  6. 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
  7. A transformer may consists of ________.

    1. one winding
    2. two windings
    3. two or more than two windings
    4. no winding
  8. In a P- type semiconductor material, the majority carriers are ________.

    1. Holes
    2. Electrons
    3. Ions
    4. Protons
  9. 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
  10. Addition of impuritirs in semiconductor material to produce more current is called

    1. intrinsic
    2. dopping
    3. bonding
    4. excitation
  11. 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
  12. 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
  13. 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
  14. 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
  15. 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
  16. There is a ________ energy gap between valence and conduction band.

    1. forbidden
    2. permitted
  17. In an N-type semiconductor material, the majority carrier are

    1. holes
    2. electron
    3. ions
    4. protons
  18. There is no voltage drop across diode when forward biased, in case of

    1. ideal diode model
    2. practical diode model
  19. 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
  20. 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