You are provided with a potentiometer x y; a jockey, J; a standard resistor, R, and other necessary apparatus.

1. Connect a circuit as shown in the diagram above.
2. Close the key. Read and record the current 10 when J is not in contact with XY.
3. Let J make contact with XY at C, such that XC = l= 25 cm. Close the key. Read and record the current l.
4. Evaluate I\(^{-1}\).
5. Repeat the procedure for four other values of I = 40, 55, 70, and 85 cm. Tabulate your readings.
6. Plot a graph of l on the vertical axis against I\(^{-1}\) on the horizontal axis.
7. From your graph, deduce the value of I when l\(^{-1}\) = 0. Evaluate \(\frac{|O}{1}\)
8. State two precautions taken to ensure accurate results.

(b)i) Explain what is meant by the potential difference between two points in an electric circuit.

ii. A piece of resistance wire of diameter 0.2m and resistance 7\(\Omega\) has a resistivity of 8.8 x 10\(^{-7}\) \(\Omega\)m. Calculate the length of the wire. [\(\pi\) = \(\frac{22}{7}\)].