Light Bulbs and Batteries
For this small experiment we were asked to find a way to make the light bulb light up with one piece of wire and a battery. The top picture shows us successfully accomplishing this. Next we wanted to make the bulb shine twice as bright. To do this we just doubled the power supply and got the result shown in the bottom picture.
For our first experiment we were asked to select a resistor and connect it to an ammeter and power supply, in which the voltage applied was known. We also used a power meter to determine the voltage at the resistor. For each trial we increased the voltage into the circuit using the power supply. We recorded our data below as well as that of the group across from us.
The data above shows the results from the experiment. The group across from us had a much smaller resistor with more wire wrapped around it. But for the most part the voltage was consistent in both experiments. The current however was very different for each group.
We took the above data and plotted it in a Current vs. Voltage graph. The results were clear. Our data clearly fit a linear relationship, meaning that Voltage and Current are directly proportional to each other. We also learned that the slope of this line was in fact the resistance of the resistor. For our group our resistance was about 28.272 while group #2's resistance was 17.745. This means that our groups resistor had greater resistance. The reason our groups resistor had much greater resistance is because it was a longer, therefore the electron had a much more difficult time traveling across it.
For our next experiment we were given several different coils of varying diameters and lengths of wire wrapped around them. One coil was made of copper and the rest were made of nickel-silver. The goal for our experiment was to determine the resistance of each coil. Using a power meter we tested each coil to see what the resistance was and got the following data. After measuring the resistance we needed to correct it by determining the resistance in the power meter. When we did this we found that the power meter had a 1.9 Ω error.
This data shows that as the length of wire became larger the resistance of the coil also increased. In order to show this relationship we plotted Length vs. Resistance.
This graph clearly shows a proportional relationship between the Length of the Wire and Resistance. As the length increased the resistance also increased.
When we looked at the effect the Area had on the resistance we found out that the relationship was actually inversely proportional. This can clearly be seen when examining the two final NS 200 coils. They had the same length but different diameters. As the diameter of the coil was increased (same as increase in area) the resistance actually decreased. This results in an inverse relationship.
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