low initially, then increases, and then continues to decrease. The reason for this error is that when the measurements were taken and the switch was removed, the next measurements were almos t immediately taken, which
meant that the temperature was not allowed to return to the initial level, causing the resistance to constantly change throughout. Moreover, the time of wait before inserting the switch back was not uniform, which meant that the temperatures were almost always different, making most of the values inaccurate. This factor is also somewhat subject to random error, as the temperature of the environment may also constantly change, although the laboratory was an air - conditioned room, wh ich controls the temperature mostly. The disparity in temperature can be reduced by letting the circuit remain open for about 1 minute before re - inserting the switch, so that the circuit’s temperature would be close to that of the room. Moreover, there was an incident where one of the wires broke, upon which it was replaced, but the readings were not re -
started from the beginning, but continued from where it was, adding on to the systematic error of the experiment. The random error is mostly reduced because averages of 5 trials across 8 different observations were taken, yet there is an improvement that can be made to reduce it even further. As seen in table 3, the fractional/percentage 8 continuously reduces as the voltage increases, since the absolute uncert ainty is constant. Since the values are used in further calculations, like division to find out resistance, the uncertainty will carry over to the new values found using it. Thus, it is beneficial to use higher intervals, for eg. 0.2 A each, to make the re adings of current and voltage higher, where the random error will not affect the final value as much as it does when smaller values are used. By making the above changes to the experiment, the readings observed will be more accurate and uniform.
- Fall '10
- Resistor, Electrical resistance