In the following potentiometer circuit AB is a uniform wire of length

1.	In the following potentiometer circuit AB is a uniform wire of length 1 m and resistance 10Ω. Calculate the potential gradient along the wire and balance length AO.
Answer» Current flowing in the potentiometer wire \(I=\frac{E}{R_{total}}=\frac{2.0}{15+10}=\frac{2}{25}A\) Potential difference across the wire \(\frac{2}{25}\times10=\frac{20}{25}=0.8V\) Potential gradient \(k=\frac{V_{AB}}{l_{AB}}=\frac{0.8}{1.0}=0.8V/m\) Now, current flowing in the circuit containing experimental cell, \(\frac{1.5}{1.2+0.3}=1A\) Potential difference across length AO = 0.3 x 1 = 0.3 V Length AO = \(\frac{0.3}{0.8}m=\frac{0.3}{0.8}\times100 \,cm=37.5\,cm\)

In the following potentiometer circuit AB is a uniform wire of length 1 m and resistance 10Ω. Calculate the potential gradient along the wire and balance length AO.

Answer»

Current flowing in the potentiometer wire

\(I=\frac{E}{R_{total}}=\frac{2.0}{15+10}=\frac{2}{25}A\)

Potential difference across the wire \(\frac{2}{25}\times10=\frac{20}{25}=0.8V\)

Potential gradient \(k=\frac{V_{AB}}{l_{AB}}=\frac{0.8}{1.0}=0.8V/m\)

Now, current flowing in the circuit containing experimental cell,

\(\frac{1.5}{1.2+0.3}=1A\)

Potential difference across length AO = 0.3 x 1 = 0.3 V

Length AO = \(\frac{0.3}{0.8}m=\frac{0.3}{0.8}\times100 \,cm=37.5\,cm\)