11. In the bridge given in the figure, the reading of the high impedance voltmeter is __________V
    

1. 1. 3.33V

   
   
   

   2. 3V

   
   
   

   3. .33V

   
   
   

   4. 2.33V

   
   
   

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1. View Hint View Answer Discuss in Forum

   Current in either branch is
   
   

   I =	10	=	1	A
   	30		3

   
   

   Vab = 20 ×	1	+ 10 ×	1	= 3.33V
   	3		3

   Correct Option: A

   Current in either branch is
   
   

   I =	10	=	1	A
   	30		3

   
   

   Vab = 20 ×	1	+ 10 ×	1	= 3.33V
   	3		3

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12. Equal resistances of 100Ω each are connected in each arm of a Wheatstone bridge which is supplied by a 2 V battery source. The galvanometer of negligible resistance connected to the bridge can sense as low current as 1μs. The smallest value of resistance that can be measured is _________

1. 1. 20

   
   
   

   2. 21

   
   
   

   3. 22

   
   
   

   4. 28

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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13. A unknown resistance is measured by substitution method. First a standard known resistance of 100Ω is connected in series with a circuit having a rheost at and a galvanometer. The battery voltage is 10 V and the setting of the rheostat is 500 Ω and the galvanometer shows a deflection of 60°. After this test, the battery voltage goes down to 9 V and when the unknown resistance is substituted for the known resistance, the galvanometer again shows a deflection of 60° with the same setting of the rheostat. The value of unknown resistance is _________

1. 1. 54

   
   
   

   2. 56

   
   
   

   3. 51

   
   
   

   4. 45

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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14. A d.c voltmeter has a sensitivity of 1000Ω/ volt. When it measures half full scale in 100 V range, the current through the voltmeter will be ________mA
    

1. 1. 50

   
   
   

   2. 51

   
   
   

   3. 47.7

   
   
   

   4. 5.0

   
   
   

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1. View Hint View Answer Discuss in Forum

   Sensitivity of d.c. voltmeter = 1000 Ω/volt For half scale in 100 V range, i.e. 50 V current through the voltmeter,
   

   I =	50	= 50mA
   	1000

   
   

   Correct Option: A

   Sensitivity of d.c. voltmeter = 1000 Ω/volt For half scale in 100 V range, i.e. 50 V current through the voltmeter,
   

   I =	50	= 50mA
   	1000

   
   

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15. The meter constant of a single-phase 240 V induction watthour meter is 400 r evolutions per kWh. The speed of the meter disc for a current of 10 amperes of 0.8 p.f. lagging will be ____________ rpm

1. 1. 12.8 rpm

   
   
   

   2. 1.8 rpm

   
   
   

   3. 12 rpm

   
   
   

   4. 11.8 rpm

   
   
   

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1. View Hint View Answer Discuss in Forum

   n = k × power × time in hour
   

   =	400 × 240 × 10 × 0.8	×	1	rph
   	100		3600

   
   = 12.8 rpm

   Correct Option: A

   n = k × power × time in hour
   

   =	400 × 240 × 10 × 0.8	×	1	rph
   	100		3600

   
   = 12.8 rpm

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