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Question
In the following potentiometer circuit, AB is a uniform wire of length 1 m and resistance 10 Ω. Calculate the potential gradient along the wire and balance length AO (= l).
Solution
Potential space gradient = `V_(AB)/I`
Using Kirchhoff’s rules,
`2=Ixx15+Ixx10=Ixx25=>I=2/25=0.08 A=>V_(AB)=Ixx10=0.8 =V`
`therefore " Potential space gradient "=(0.8/1)=0.8V/m`
Balance length = l
Potential difference across the balance length = Potential gradient × l
Potential difference across AO = 0.3 × 1 = 0.3 V
`therefore 0.3 V="Potential space gradient" xxI=>0.3=0.8xxI=>I=0.375 m=37.5`
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