Electrical Fundamentals Quiz Exam!

52 Questions | Total Attempts: 444

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Electrical Fundamentals Quiz Exam! - Quiz

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Questions and Answers
  • 1. 
    Which of the following circuit elements stores energy in the electromagnetic field?
    • A. 

      condenser    

    • B. 

      Inductance  

    • C. 

      Resistance

  • 2. 
     The property of a coil by which  a  counter emf is induced  in it,when the current  through the coil changes, is known as
    • A. 

      Self - inductance

    • B. 

      Mutual Inductance

    • C. 

      Series aiding inductance

  • 3. 
    An alternator  converts ______ energy into ____energy.
    • A. 

      Potential to kinetic

    • B. 

      Mechanical to electrical

    • C. 

      Electrical to mechanical

  • 4. 
    In a single-phase alternator all four stator coil groups are connected in series so that the voltage induced in each winding add to give a total voltage that is ______ times the voltage in any one winding.
    • A. 

      Three

    • B. 

      Double

    • C. 

      four

    • D. 

      None

  • 5. 
    For  a frequency of 400 Hz , the time period shall be
    • A. 

      0.25 seconds 

    • B. 

      0.0025 seconds

    • C. 

      0.025 seconds

    • D. 

      0.005seconds

  • 6. 
    The  period of a wave is 
    • A. 

      None

    • B. 

      Time required to complete one cycle

    • C. 

      Expressed in amperes

    • D. 

      Same as frequency

  • 7. 
    In a single-phase alternator one rotor pole is in the same position relative to a stator winding as any other rotor pole, all stator polar groups are cut by equal numbers of magnetic lines of force at any time as a result.
    • A. 

      The ac voltages are in phase

    • B. 

      Total induce voltage is 4 times the voltage induced in any one winding.

    • C. 

      The voltage induced in any one winding have the same amplitude

    • D. 

      All of the above

  • 8. 
    The major difference between an alternator is the method of connection to the external circuit, that is the alternator is connected to the external circuit by______, but the DC generator is connected by a commutator.
    • A. 

      Slip rings, brush

    • B. 

      Slip rings,commutator

    • C. 

      Commutator,slip rings

    • D. 

      None of the above

  • 9. 
    Unless  otherwise specified, any value given for  current or  voltage in an AC circuit is assumed to be:
    • A. 

      Maximum

    • B. 

      Instantaneous  

    • C. 

      Effective

    • D. 

      Average   

  • 10. 
    High  voltage alternator is usually of the stationary armature rotating field type because:
    • A. 

      It has commutator and brush

    • B. 

      Slip ring have sort life

    • C. 

      The slip ring have a hazard arc over

    • D. 

      both b and c

  • 11. 
    In delta connection
    • A. 

      Phase voltage =line voltage

    • B. 

      31/2 phase voltage = line voltage

    • C. 

      Phase voltage =3 ½   line voltage

    • D. 

      None of the above

  • 12. 
    In a  wye connection, the total voltage or line voltage across any two phase is a vector sum of the individual phase voltages. For balance conditions the line voltage is _______ times the phase voltage.
    • A. 

      1.414     

    • B. 

      1.73         

    • C. 

      0.707

  • 13. 
    A transformer
    • A. 

      Changes electrical energy into mechanical energy

    • B. 

      changes electrical energy of a given voltage into electrical  energy  at a  different  voltage   level

    • C. 

      Changes  mechanical  energy  into electrical  energy

  • 14. 
    MTCS 1) a transformer can be used for pulsating DC 2) Transformer consist of two coils which are electrically connected
    • A. 

      Only  1) is true     

    • B. 

      Only 2) is true  

    • C. 

      Both are true  

    • D. 

      None

  • 15. 
    No transformer can be constructed 100% efficient because
    • A. 

      Eddy current loss

    • B. 

      Hysteresis

    • C. 

      Leakage flux      

    • D. 

      All

  • 16. 
    The measure of how well the flux of primary is coupled with the secondary is called
    • A. 

      Coefficient of self inductance

    • B. 

      Coefficient of coupling

    • C. 

      Turns ratio      

    • D. 

      all

  • 17. 
    The primary of a transformer develops 50,000 lines of force and only 45,000 lines cut acrose secondary ,the coefficient of coupling would be
    • A. 

      50%   

    • B. 

      0.5  

    • C. 

      0.9 

    • D. 

      None

  • 18. 
    A direct connected direct current generator is also called as ______ alternator.
    • A. 

      Separately excited  

    • B. 

      Self excited

    • C. 

      Brush less        

    • D. 

      None

  • 19. 
    In __________ transformer the primary winding  and  secondary  windings are connected magnetically  as  well  as  electrically
    • A. 

      Audio   

    • B. 

      Auto    

    • C. 

      Power    

    • D. 

      RF

  • 20. 
    An  auto transformer  will  have
    • A. 

      Less cost  

    • B. 

      Better regulations

    • C. 

      Low loss as compare to ordinary two  windings transformers of the same rating

    • D. 

      All of the above

  • 21. 
    Unit of attenuation _________
    • A. 

      Joule

    • B. 

      Decibel  

    • C. 

      Watts

  • 22. 
    Iron loss are also called as
    • A. 

      Copper loss   

    • B. 

      Ohmic  loss  

    • C. 

      Core loss    

    • D. 

      All                       

  • 23. 
    Copper loss is ______loss
    • A. 

      I square Rt   

    • B. 

      Ohmic      

    • C. 

      Both a) and b)

  • 24. 
    Efficiency of a transformer is given by
    • A. 

      Output power /input power

    • B. 

      Input power /output power  

    • C. 

      Out put magnetic lines of  force /input magnetic lines of force

  • 25. 
    Which  filter  is used to pass  particular band of frequency?
    • A. 

      Band pass     

    • B. 

      Band stop    

    • C. 

      Rejection filter

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