1.6 (b)
Class Experiment 1
The series circuit set up to investigate current should be set up again, with the lamps in the same order. Firstly a voltmeter should be used to find the p.d. across each component. Then with the negative terminal of the voltmeter connected to the negative terminal of the cell, the positive lead is used as a floating lead to be put around the circuit.
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Analysis
The pupils should be allowed to deduce their own conclusions from the floating lead, and then the relationship between the terminal p.d. and the sum of the idividual p.d.'s. This should be indicated that it is due to the conservation of energy. The pupils may also plot a graph of p.d. against position around the circuit and have a look at the potential gradient and compare that to the positions of the ammeter and different lamps, as well as their brightness.
