## Few students use the Voltage-Resistance-Current (VRI) model of a series circuit

Electricity and Magnetism

Misconception Few students use a model of a series circuit as a system in which an agent (whose strength is measured in volts) causes an electric current around the circuit, the size of which is also determined by the resistance of the circuit (the VRI model).

### Diagnostic Resources

The following worksheets may help to identify whether students hold this particular misconception.

• Relationship between Current and Voltage and Resistance (11-14)

Source - SPT / El03PN02

This resource offers teacher some guidance on how to successfully disentangle the concepts of electric current, voltage and resistance for students.

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• Simple measurements and calculations (14-16)

Source - SPT - Ee01YA05

Introduce a number of circuits where the goal is to find the effective resistance of the circuit. Students need to choose where to put the ammeter and voltmeter, and then transfer their choice and readings to the calculations templates.

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• Measuring resistance with a voltmeter and an ammeter (11-16)

Source - Practical physics/ Electric circuits and fields/ Ohm's Law and resistance/ ...

This series of experiments should give students practice in taking a pair of current and potential difference readings for various components so that the resistance of the component can be calculated from V/I = R.

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• Episode 108: Resistance (16-19)

Source - TAP / Electricity / Electrical resistance / ...

The idea of resistance should be familiar (although perhaps not secure) from pre-16 science course, so there is no point pretending that this is an entirely new concept. A better approach is to draw out what they know. The aim of this first episode is to provide a quantitative definition for resistance

( R = V / I) which reinforces the qualitative notion that more resistance means less current. In addition, we will look at Ohm’s law, which is not the same thing as the definition of resistance.

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## References

The following studies have documented this misconception:

• Liégeois, L.; Chasseigne, G.; Papin, S. and Mullet, E. () Improving high school students' understanding of potential difference in simple electric circuits. International Journal of Science Education, 25 (9)

1129-1145.

• Millar, R. and King, T. () Students’ understanding of voltage in simple series electric circuits. International Journal of Science Education, 15 (3),

339-349.

• Dupin, J. J. and Johsua, S. () Conceptions of French pupils concerning electric circuits: Structure and evolution. Journal of Research in Science Teaching, 24 (9),

791-806.