To investigate whether the two resistors and the bulb given is an ohmic or non-ohmic conductor.

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Ohmic Conductors (ELC)

Physics Portfolio By Clement Ng 12.6

Aim: To investigate whether the two resistors and the bulb given is an ohmic or non-ohmic conductor.

Method:

  • Arrange apparatus as shown in the below circuit diagram
  • Replace R with the tested unknown resistor or bulb
  • Adjust the variable power supply until volt meter reads of consecutive even numbers, 2, 4, 6…12
  • In each case, record down the corresponding current value on the amp meter
  • After the first set of readings are collected, redo the experiments to obtain some check readings
  • Repeat method until all the two resistors and the bulb is tested
  • Using the results, calculate the averages and plot graphs of V against I, remember to include the error bars
  • Using the graphs, work out the max/min/normal gradients and calculate the resistance for each item. Remember to specify the error in the final resistance value by using the max/min gradient values.
  • Compare the graph of a resistor and a light bulb and comment on the behavior
  • Write conclusions and evaluations

Diagram:

Skill 3 Data Collection

Resistor 1 (#8):

Resistor 2 (#3):

Light Bulb

Skill 4 Data Processing

Resistor 1 (#8):

Resistor 2 (#3):

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Light Bulb

Please note that all data processing graphs are presented at the last page of this report.

Skill 5 Conclusions and Evaluations

Conclusions

To conclude from the V/I graphs, Resistor 1 (#8) has a resistance of 53.3Ω (±6Ω). Resistor 2 (#3) has a resistance of 20Ω (±2Ω). The uncertainty values here are deduced by using the min/max resistance error values, calculated from the graphs. On the other hand, the bulb has an approximate resistance value of 7.4Ω. However, as you can see from the graph, the line is not linear, but instead curved. Since this is the ...

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