Lab 14: Potential of Continuous Charge Distribution

First thing we did was to calculate the electric potential from a continuos charge distribution at a distance x from a point P. We used V = kq/r, The electric potential at the top is V = kq/x, since P is at x distance apart from the ring. For the middle is V = kq/sqrt(x^2+2a^2), we used the pythagorean theorem to find r, and finally for the bottom is V = kq/sqrt(x^2+4a^2).

After some derivations, we did an example of electric potential due to a finite length line-charge. First, we compute the results in excel using the formula V = k.lambda/sqrt(x^2+y^2). The obtained result was V = 2.47x10^6, by dividing the rod into 20 pieces.

Then, we did by hand the same procedure, dividing the rod into 20 pieces. Through some algebra, we got the equation above. Then we just used the given values and our electric potential was the same as first calculated in excel.

Professor Mason showed us 2D and 3D visual representation of equipotentials and electric field lines. In the 3D applet, we saw how the electric field lines from one sphere gets and repelled away and moves into the other sphere.

For the electric potential lab, we used a multimeter to calculate the potential difference on the conductive paper from one metallic mark to x distance from it by setting the power supply at 15V. First we calculated each potential at different separations going to the left, then we calculated the potentials to the right.

This is a table of values gathered during the experiment.