The following questions are guide lines for your exposé.

  Give a full description of the circuit.

  Give the value of current’s intensity I and the potential difference U for the generator when the rheostat is at its maximum value.

  How do I and U vary when R decreases ? Discuss.

  Give the open circuit voltage of the generator.

  R0 is the internal resistance of the generator. Explain how to determine on the graph the value of R0.

  The 2 machines used for the experimental work are reversible. Explain the term “reversible”.