Ohm's Law - Resistance?
Below are the results of an experiment my group did at school while I was away sick. The experiment was to determine the resistance of an unknown resistor. The Resistor's actual resistance was 2.2 ohms, but the results (as you can see) are all over the place. The circuit included a voltmeter, ammeter and rheostat (which was adjusted with each trial) I have been reading and reading about Ohm's law, circuits and percentage errors, but I have only managed to confuse myself more. Basically, I need to explain the results and if the percentage errors are acceptable, but I am having trouble understanding all of this.
1. Can someone please explain why these results likely occurred (errors in the experiment)? Do the voltmeter, ammeter abd reheostat impact on resistance? and;
2. Are there any relationships between the results that I should highlight (like the amps dropping as the resistance increases in Trails 3 and 4 where the voltage is constant)?
I am so confused. Please help.
Trial, Current, Voltage, Resistance, Percentage Error
1 0.74, 1.5, 2.027, -7.863%
2 0.82, 1, 1.2195, -44.5681%
3 0.2, 0.5, 2.5, 13.53%
4 0.14, 0.5, 3.5714, 62.336%
