16. The sensitivity of an instrument is the

1. 1. smallest increment in the input that can be detected with certainty

   
   
   

   2. largest input change to which the instrument fails to respond

   
   
   

   3. ratio of the change in the magnitude of the output to the corresponding change in the magnitude of the input

   
   
   

   4. closeness of the output values for repeated applications of a constant input

   
   
   

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1. View Hint View Answer Discuss in Forum

   Sensitivity of an instrument is ratio of the change in the magnitude of the output to the corresponding change in the magnitude of the input.

   Correct Option: C

   Sensitivity of an instrument is ratio of the change in the magnitude of the output to the corresponding change in the magnitude of the input.

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17. ‘Creep’ is energy meters can be prevented by

1. 1. using extra turns on the voltage coil

   
   
   

   2. having two holes on opposite sides of the disc

   
   
   

   3. using a stronger brake magnet

   
   
   

   4. using steel laminations of high permeability

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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18. The effective reactance of an inductive coil

1. 1. increases because of stray capacitance as the frequency increases

   
   
   

   2. decreases because of stray capacitances as the frequency increases

   
   
   

   3. remain the same irrespective of the increase in frequency even if stray series capacitances are present

   
   
   

   4. none of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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19. Consider the following statements about LVDT as a transducer:
    1. The relationship between input displacement and output voltage is almost linear.
    2. The range of displacement that can be measured is wide.
    3. It does not form a loading on the mechanical system. Of these statements

1. 1. 1, 2 and 3 are correct

   
   
   

   2. 2 and 3 are correct

   
   
   

   3. 1 and 2 are correct

   
   
   

   4. 1 and 3 are correct

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: D

   NA

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20. A shunt type ohmmeter is shown in the figure below. With R_x disconnected, the meter reads full scale. S represents the meter current as a fraction of full scale current with R_x connected such that
    

    S =	Rx
    	RxRp

    
    
    The value of R_p is given by

1. 1. R_m

   
   
   

   2. R₁ + R_m

   
   
   

   3. R1Rx
      (R1Rm)

   
   
   

   4. R1Rm
      (R1Rm)

   
   
   

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1. View Hint View Answer Discuss in Forum

   Iƒs =	E
   	R1 + Rm

   
   With R_x connected,
   

   Im =	Rx	E
   	R1 + Rx	R1 + (RmRx)/(Rm + Rx)

   
   

   =	R2 + R3	=	ERx
   	(R1 + Rx)		Rx + (R1Rm)/(R1 + Rm)

   
   

   = Iƒs	Rx
   	Rm + Rp

   
   

   where, Rp =	R1Rm
   	(R1 + Rm)

   Correct Option: D

   Iƒs =	E
   	R1 + Rm

   
   With R_x connected,
   

   Im =	Rx	E
   	R1 + Rx	R1 + (RmRx)/(Rm + Rx)

   
   

   =	R2 + R3	=	ERx
   	(R1 + Rx)		Rx + (R1Rm)/(R1 + Rm)

   
   

   = Iƒs	Rx
   	Rm + Rp

   
   

   where, Rp =	R1Rm
   	(R1 + Rm)

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