basic electrical test

• 1.       The DC generator works on the principle of?

  A] Fleming’s left hand rule

  B] Fleming’s right hand rule

  C] Lenz law

  D] none of the above                                     Ans: b

  
  

  2.       A 3 phase 4 wire system is commonly used for ?

  A] primary distribution

  B] secondary distribution

  C] primary transmission

  D] secondary transmission                          Ans:b

  
  

  3.       A current  is said to be alternating when it changes in?

  A] magnitude only

  B] direction only

  C] both magnitude and direction

  D] none                                                                                Ans:c

  
  

  4.       The slip of an induction motor normally does not depend on

  A] rotor speed

  B] synchronous speed

  C] shaft torque

  D] core loss component                                                Ans:d

  
  

  5.       The frequency of voltage at the secondary of a transformer is

  A] greater than that of primary

  B] equal to that of primary

  C] less than that of primary

  D] none of the above                                     Ans:b

  
  

  6.       Which of the following power plant is least reliable

  A] wind

  B] tidal

  C] geothermal

  D] solar                                                                                Ans:a

  
  

  7.       DC motors are still preferred for use in

  A] electric excavators, steel mills and carnes

  B] lathe and machine tools

  C] flour mills and jaw crushers

  D] paper industry                                            Ans:a

  
  

  8.       The highest transmission voltage in india is

  A]750kv

  B] 400kv

  C] 220kv

  D] 132kv                                                               Ans:b

  
  

  9.       A negative sequence relay is commonly used to protect

          (A) an alternator  

  (B) an transformer

   (C) a transmission line 

  (D) a bus bar                                                      Ans:a

  
  

  10.   For enhancing the power transmission in along EHV transmission line, the most

  preferred method is to connect a

   (A)  Series inductive compensator in the line

   (B)  Shunt inductive compensator at the receiving end

   (C)  Series capacitive compensator in the line

  (D)  Shunt capacitive compensator at the sending end   Ans:c    

  
  

  11.  In a series RLC circuit that is operating above the resonant frequency, the current
  A. lags the applied voltage B. leads the applied voltage C. is in phase with the applied voltage D. is zero Ans:a
  12.  If the resistance in parallel with a parallel resonant circuit is reduced, the bandwidth
  A. disappears B. becomes sharper C. increases D. Decreases Ans:d
  13.  If the value of C in a series RLC circuit is decreased, the resonant frequency
  A. is not affected B. increases C. is reduced to zero D. Decreases Ans:b
  	14.  If two currents are in the same direction at any instant of time in a given branch of a circuit, the net current at that instant
  	A. is zero B. is the sum of the two currents C. is the difference between the two currents D. cannot be determined Ans:b
  15.  The Thevenin equivalent voltage is
  A. equal to the source voltage B. the same as the load voltage C. the open circuit voltage D. none of the above Ans:c
  16.  In a -connected source feeding a Y-connected load,
  A. each phase voltage equals the difference of the corresponding load voltages B. each phase voltage equals the corresponding load voltage C. each phase voltage is one-third the corresponding load voltage D. each phase voltage is 60° out of phase with the corresponding load voltage Ans:a
  17.   Polyphase generators produce simultaneous multiple sinusoidal voltages that are separated by
  A. certain constant phase angles B. certain constant frequencies C. certain constant voltages D. certain constant currents Ans:a
  18. A given power supply is capable of providing 6 A for 3.5 h. Its ampere-hour rating is
  A. 0.58 Ah B. 2.1 Ah C. 21 Ah D. 58 Ah Ans:c
  19. A certain appliance uses 350 W. If it is allowed to run continuously for 24 days, how many   kilowatt-hours of energy does it consume?
  A. 20.16 kWh B. 201.6 kWh C. 2.01 kWh D. 8.4 kWh Ans:B
  20. How many primary volts must be applied to a transformer with a turns ratio of 0.1 to obtain a secondary voltage of 9 V?
  A. 9 V B. 90 V C. 900 V D. 0.9 V Ans:b
  21. A 1.5 k resistor and a coil with a 2.2 k inductive reactance are in series across an 18 V ac source. The power factor is
  A. 564 B. 0.564 C. 6.76 D. 55.7 Ans:b
  22. To increase the current in a series RL circuit, the frequency
  A. should be increased B. should be decreased C. should be constant D. cannot be determined without values Ans:b
  23. A sine wave voltage is applied across a capacitor. When the frequency of the voltage is decreased, the current
  A. increases B. remains constant C. decreases D. Ceases Ans:c
  24. Two 1.5 V cells are connected series opposing across two 100  resistors in series. Total current flow is
  A. 15 mA B. 5 mA C. 2 mA D. 0 A Ans:d
  25. A phasor represents
  A. the magnitude and a quantity direction B. the width of a quantity C. the phase angle D. the magnitude of a quantity

  
  

                        Ans:a

  
  

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