The main objective of this laboratory experiment is to examine the resistance through a light bulb and through a variety of series and parallel combination of bulbs. Another objective of the bulbs experiment is the verification of Ohm’s law by analyzing the light and voltage through a bulb. Ohm’s law gives that the voltage is directly proportional to the current, with the constant value being the resistance. Therefore, in a graph of voltage and current, the gradient will be the resistance. In this experiment, the resistance of various bulbs will be obtained through the use of Ohmmeter and then compared by the gradient of their V-I graphs to find the percent error.
In the first set up include individual bulbs A, B, and C, the percent error was 39.15%, 19.87% and, 43.49% respectively. The series and parallel combinations of the three bulbs had 15.33% and 4.68% respectively. The first parallel and series combination had a percent error of 18.3% while the second parallel and series combination had a percent error of 19.14%. From the percent errors, it is evident that the parallel combination gives the lowest percent error, however, the rest of the combinations indicate a fairly high percent error. The high percent error was attributed to the heating of the bulbs causing a variation in the resistance of the bulbs.
The objective of the experiment was achieved where the resistance of the light bulbs was measured using the voltage and current through the bulbs. These resistances were compared with that measured with the Ohmmeter and the percent errors obtained. The percent errors were fairly high and attributed to the heating of the bulbs which affected the resistance of the bulb. The resistance can be reduced letting the bulbs cool after each test.
The Ohms law is not a universal law since it does not apply in various cases. In materials like semiconductors, the Ohms law does not apply in the describing the voltage and current relationship. In Diodes, the voltage and current relationships is non-ohmic, which means that the relationship is not linear.