You have been provided with an accumulator E, a standard resistor Rx, two resistance boxes RB\(_{1}\) and RB\(_{2}\), two keys K\(_{1}\) and K\(_{2}\) and other necessary apparatus.

1. Measure and record the e.m.f of the accumulator.
2. Connect a circuit as shown above.
3. Set the resistance R, in the resistance box such that R in RB\(_{1}\) = R in RB\(_{2}\) = 1\(\Omega\).
4. With K\(_{1}\) open and K\(_{2}\) closed, measure and record the potential difference V across the standard resistor Rx. (v) Close K, and K,. Read and record the potential difference V\(_{o}\) across Rx.
5. Evaluate V\(_{1}^{-1}\)
6. Repeat procedure (v) for four other values of R = 2, 3, 4 and 5\(\Omega\) respectively. In each case, ensure that the value of R in RB\(_{1}\) is equal to the value of R in RB\(_{2}\).
7. Evaluate V\(_{1}^{-1}\) in each case. Tabulate your readings.
8. Plot a graph of V\(_{1}^{-1}\) on the vertical axis against R on the horizontal axis starting both axes from the origin (0,0).
9. Determine the slope, s, of the graph and the intercept on the vertical axis.
10. Evaluate y = \(\frac{1}{s}\)
11.  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 cell has an e.m.f. of 3 V. When it is connected across a resistor of resistance 4\(\Omega\), a current 0.5A passes through the circuit. Calculate the internal resistance of the cell.