Electric Potential (14th Day)

 Spring 2015
Professor Mason
April 16 Class

Electric Potential in Microsoft Excel
The first thing we needed to do in class was to calculate the electric potential of 20 charges in excel by using an equation of [V = kq/(sqrt of a^2 +x^2)], given a is 0.3 and x is 0.2, while k is a constant of 9e9 and q is a charge that is 2e-5.After we got one charge by using the calculation, we could just copy the whole numbers for 20 times, and calculate the total as shown in the picture attached on the left. Potential difference happens due to continuous charge distributions. We did another experiment with excel in the middle of the class after the first one. However, this one is more complicated because it is based on a triangle shown on the picture attached below. There is a rod, and the rad has 20 charges attached in it .We had to calculate the electric potential in the 16th charge, but it started at in the middle of charge 0 and charge 1; therefore we measured it from 0.5 to 16th charge in excel.

 Electric Potential Calculations
After we did an experiment with Microsoft Excel, we did another calculation by hand, given the picture as shown below. The ring has 20 point charges acting on a single point x distance from ring. Ring has a radius of a. Given the charge for 20 charges is 20 micro C, therefore, we had to divide it by 20 and multiply it by 20 because it has 20 charges. We used the same equation as the one in Microsoft Excel, which is [V = kq / sqrt (a^2 + x^2)].

 On the next one, we were asked to calculate the electric potential in terms of theta as shown in the picture below. We knew that the diameter of that circle is 2a, and the distance from the edge of that diameter to P2 is defined by x. Therefore, we found out that [tan theta = 2a/x ], [sin theta = 2a / sqrt(4a^2 + x^2)], and [cos theta = x / sqrt (4a^2 + x^2)]. After we substitute and simplify the formula, we found out that the electric potential in terms of theta could be [V = kq cos theta / x] as shown in the picture below.

 After we finished with all the electric potential calculations, we were asked to draw an equal electric potential in a circle, and the result is shown below in the picture. Other than that, we were also asked to draw an equal electric potential between two rods, and we found out that there are several answers for it, and the result vector is shown in the picture attached below.

Electric Measurement Experiment

 In this experiment, we knew for sure that positive charges is always going towards negative charges. First, we set up the power supply to 15 V, then connect all the wires to the yellow wires shown in the picture above. We also needed to connect another wire to the red machine in the picture above. We used the tip of the wire that are connected to the red machine, and place it on the metal that is attached to the yellow wires. We had to measure the numbers shown in the red machine from a certain point to another certain point. Next, we had to make a table based on the numbers we got from the red machine in order to calculate the electric potential total of this experiment.