66. The measuring instrument which utilize the electrostatic effect are:
    

1. 1. Ammeters and voltmeters
      

   
   
   

   2. Voltmeters and wattmeters
      

   
   
   

   3. Ammeters and wattmeters
      

   
   
   

   4. DC ampere hour meters and ammeters

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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67. Instrument used for DC measurement alone is:
    

1. 1. Moving iron type
      

   
   
   

   2. Permanent magnet type
      

   
   
   

   3. Electrodynamic type
      

   
   
   

   4. Induction type

   
   
   

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   Permanent magnet type instrument is used for DC measurement only.
   

   Correct Option: B

   Permanent magnet type instrument is used for DC measurement only.
   

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68. Instrument used for AC measurement alone is:
    

1. 1. Permanent magnet type
      

   
   
   

   2. Hot wire type
      

   
   
   

   3. Electrostatic type
      

   
   
   

   4. Induction type

   
   
   

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   Induction type instrument is used for AC measurement only.
   

   Correct Option: D

   Induction type instrument is used for AC measurement only.
   

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69. Which of the following instruments will have the same calibration on both AC and DC?
    

1. 1. Electrodynamometer type
      

   
   
   

   2. Moving iron type
      

   
   
   

   3. Moving coil type
      

   
   
   

   4. Induction type

   
   
   

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   Electrodynamometer type instrument will have the same calibration on both AC and DC.

   Correct Option: A

   Electrodynamometer type instrument will have the same calibration on both AC and DC.

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70. The advantage of electrodynamometer type instruments:
    As the coils are air cored, these instruments as free from

1. 1. hysteresis and eddy current errors
      

   
   
   

   2. Low torque/weight ratio
      

   
   
   

   3. Large operating current
      

   
   
   

   4. Non-uniform scale

   
   
   

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   The advantage of electrodynamometer type instrument is that these instruments are free from hysteresis and eddy current errors.

   Correct Option: A

   The advantage of electrodynamometer type instrument is that these instruments are free from hysteresis and eddy current errors.

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