26 September 2016

ELECTRICAL QUETIONS AND ANSWERS-MCQ 11 - ETO


QUESTIONS AND ANSWERS FOR ETO

1. The opposition to the establishment of magnetic lines of force in a magnetic circuit is called the circuit's_______.      
A. resistance      
B. reluctance      
C. impedance     
D. inductance     
Ans : B

2. The insulation resistance of electric equipment and   machinery should be tested for the lowest normal insulation values _____________.               
A. immediately after shutting down the machine    
B. every time the brush rigging is adjusted
C. immediately after starting up the machine          
D. every 30 days whether the machine is in use or not          
Ans : A

3. Which of the terms listed best describes a compound-woundDC generator having a higher voltage at no load than at full load?               
A. Flat compounded          
B. Over compounded        
C. Under compounded     
D. Terminal compounded
Ans : C

4. The purpose of squirrel-cage windings in a synchronous motor is to ______________.          
A. provide more precise balancing               
B. produce a higher power factor 
C. eliminate arcing between the stator and the frame          
D. provide a means for starting    
Ans : D

5. High vacuum diodes, gas-filled diodes, and germanium  semiconductor diodes may all be used as _____________.     
A. potentiometers            
B. rectifiers         
C. power sources              
D. photocells      
Ans : B

6. Local action in a dry-cell, or lead-acid storage battery is the process whereby ________________.   
A. hydrogen gas is liberated           
B. the electrolyte compensates for overcharging    
C. potassium hydroxide absorbs carbon dioxide from the air               
D. the battery becomes discharged without being connected to a load            
Ans : D

7. The RMS value of a sine-wave current may also be expressed as the _____________.           
A. average value
B. maximum value            
C. effective value               
D. instantaneous value    
Ans : C

8. On tank vessels with an electrically-driven capstan, the motor should be meggered periodically to test _____________.          
A. insulation resistance   
B. eddy currents
C. capacitance   
D. armature reactance    
Ans : A

9. A triac thyristor functions as a control device and is  basically ________________. 
A. two NPN transistors in parallel with a common base lead               
B. a diode in series with a temperature sensitive capacitor 
C. two back-to-back SCR's with a common gate lead              
D. a triode tube with an extra heavy grid element  
Ans : C

10. The speed of a squirrel cage induction motor is determined by the _____________.            
A. diameter of the stator
B. number of stator poles               
C. rotor winding resistance            
D. bar resistance of the conducting rotor  
Ans : B

11. What is the maximum current allowed to be drawn from the secondary of a 2 KVA step-down transformer with a turns  ratio of four to one if connected across a 440 volt line?
A. 1.1 amps         
B. 4.5 amps         
C. 18.1 amps      
D. 22.7 amps      
Ans : C

12. The conversion of the throttle command voltage to thesignal necessary to achieve the desired shaft RPM isaccomplished by the _____________.               
A. ahead or astern function generator of the throttle control circuit
B. feedback resistor of the summing amplifier circuit             
C. operational amplifiers in the autorotation circuit               
D. long time constant amplifier circuit        
Ans : A

13. The apparent power in a purely inductive circuit is also known as _____________.               
A. true power     
B. lead power     
C. induced power              
D. reactive power             
Ans : D

14. The multiple prefix "giga" (G) means ____________.     
A. thousand (10 to the 3rd power)               
B. million (10 to the 6th power)     
C. billion (10 to the 9th power)      
D. trillion (10 to the 12th power)  
Ans : C

15. Copper is often used as an electrical conductor because it _______________.      
A. has high resistance at low temperatures              
B. has a highly polished surface    
C. is able to pass current with little opposition         
D. holds insulation together well  
Ans : C

16. Under which of the listed conditions can the engine room retake the throttle control from the bridge?          
A. Any time it is deemed necessary.            
B. Only with the master's permission.        
C. After a 10 minute delay to the input command.  
D. Only after the throttle has been placed in stop.  
Ans : A

17. A hydrometer indicates specific gravity by comparing the _____________.             
A. density of a substance in water with the density of the same substance in air          
B. differences in weight between water and the liquid measured      
C. mass of substance measured with the density of the same  substance       
D. buoyancy of an object in water with the buoyancy of the same object in the liquid being measured   
Ans : D

18. The unit of apparent power in a purely inductive circuit is called the _____________.          
A. kva    
B. var    
C. emf   
D. watt 
Ans : B

19. A grounded switch or cable will be indicated by a   megohmmeter reading of _____________.         
A. infinity             
B. "zero"              
C. being unsteady in the high range             
D. being unsteady in the low range
Ans : B

20. Regarding battery charging rooms, ventilation should be  provided __________.  
A. at the lowest point of the room               
B. horizontally near the batteries 
C. at the highest point of the room              
D. only when charging is in progress           
Ans : C

21. In a 15 HP induction-type motor with a cage rotor, the  current required at standstill to produce starting torque is approximately ____________.  
A. half the full load current             
B. equal to the full load current     
C. five times the full load current  
D. ten to twenty times the full load current              
Ans : C

22. A single-phase induction motor having a relatively high  starting torque, is the ___________.          
A. shaded pole motor       
B. wound-rotor motor      
C. capacitor-start motor 
D. resistance-start motor               
Ans : C

23. A common type of protective covering used on electrical  conductors is _____________.   
A. plain paper     
B. fibrous braid  
C. silver sheathing            
D. babbitt sheathing        
Ans : B

24. The main difference between an electron tube and a   transistor is the _____________.    
A. type of function they can perform           
B. reaction of electron flow through a gas or vacuum in a  transistor
C. reaction of electron flow through a semiconductor when  placed in a tube 
D. reaction of electron flow through a semiconductor used to form a transistor           
Ans : D

25. Which of the following statements concerning the specific gravity of a battery electrolyte is true?  
A. The electrolyte becomes less dense when it is cooled.     
B. The specific gravity reading is lowered when the electrolyte is heated.       
C. The most accurate hydrometer reading is obtained immediately after water is added.         
D. The temperature does not affect the specific gravity of the electrolyte.     

Ans : B

"I wanted freedom, open air and adventure. I found it on the sea."
— Alaine Gerbault, Sailor

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ELECTRICAL QUETIONS AND ANSWERS-MCQ 11 - ETO
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