11. An instrument has sensitivity of 1000 ohm/volt. On the 100 volt scale. This instrument will have internal resistance of:
    

1. 1. 10 ohms
      

   
   
   

   2. 10,000 ohms
      

   
   
   

   3. 1,00,000 ohms
      

   
   
   

   4. 1,000 ohms

   
   
   

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1. View Hint View Answer Discuss in Forum

   The sensitivity of voltmeter is given by relation Sensitivity,
   

   S =	1	ohms/volt
   	Ifsd

   
   where, I_fsd = full scale current
   S = R/V
   or
   R = SV
   = 1000 × 100 = 1,00,000 ohms

   Correct Option: C

   The sensitivity of voltmeter is given by relation Sensitivity,
   

   S =	1	ohms/volt
   	Ifsd

   
   where, I_fsd = full scale current
   S = R/V
   or
   R = SV
   = 1000 × 100 = 1,00,000 ohms

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12. Induction method of testing is used for:
    

1. 1. Short circuit fault in the cables
      

   
   
   

   2. Open circuit fault in the cables
      

   
   
   

   3. Short circuit and ground fault in the cables
      

   
   
   

   4. Open circuit and ground fault in the cables

   
   
   

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1. View Hint View Answer Discuss in Forum

   Induction method of testing is used for open circuit fault in the cables.

   Correct Option: B

   Induction method of testing is used for open circuit fault in the cables.

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13. Two 300 V d.c. voltmeters having resistances of 15000Ω and 5000Ω are connected in series. The safe voltage which can be measured by this combination is:
    

1. 1. 600 V
      

   
   
   

   2. 400 V
      

   
   
   

   3. 300 V
      

   
   
   

   4. 200 V

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: B

   NA

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14. X and Y plates of a CRO are connected to unequal voltages of equal frequency with phase shift of 90°. The Lissajous figure on the screen will be:
    

1. 1. Circle
      

   
   
   

   2. Straight line
      

   
   
   

   3. Ellipse
      

   
   
   

   4. Figure of eight

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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15. To use miliammeter as voltmeter series resistance:
    where,
    V = Required voltage
    I_m = Full scale reading
    R_m = Meter resistance
    n = Multiplying factor of meter

1. 1. R_s = R_m (n – 1)
      

   
   
   

   2. R_s = V/I_m = R_m
      

   
   
   

   3. R_s = V/I_m + R_m
      

   
   
   

   4. None of these

   
   
   

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1. View Hint View Answer Discuss in Forum

   To use milliammeter as voltmeter series resistance.
   

   Rs =	V	- Rm
   	Im

   
   or
   

   Rs =		V	- 1		= Rm(n-1)
   		ImRm

   
   where,
   n = V/V_m
   = Voltage to be measured/Voltage of the meter
   where,
   V = Required voltage
   I_m = Full scale reading
   R_m = Meter resistance
   

   Correct Option: B

   To use milliammeter as voltmeter series resistance.
   

   Rs =	V	- Rm
   	Im

   
   or
   

   Rs =		V	- 1		= Rm(n-1)
   		ImRm

   
   where,
   n = V/V_m
   = Voltage to be measured/Voltage of the meter
   where,
   V = Required voltage
   I_m = Full scale reading
   R_m = Meter resistance
   

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