3/25/2015 electric field

From gravity field to electric field, we define some properties that an electric field will have. We think that the electric is caused by charging the particles and its magnitude is influenced by the charge and distance between the particles. What is more, it is a vector.

We list some necessary steps to figure out an electric field. Notice that we eventually want to write an electric field in a unit vector form to label its direction since it is a vector. In the end, we write a more general form to calculate electric field including its direction as well as magnitude.

Before we write the python program, we firstly predict what will the minimum work source code will generate and draw it on the white board. This graph shows the xyz plane and where the original point will be.

This is the sample run of the program. It shows one electric field line and its direction.

By modifying the source code, the program will finally be able to show some electric field line in a 3D view. Since we make it have positive charges, the direction of those electric line is pointing away from the particle.

We modify the code again so that it will show us the magnitude of electric field as well as just showing their direction, and we record it on the white board.

This is one sample calculation to calculate the electric field at a certain point in a system that is made up by more than one particle charges. We express it in unit vector form.

Making it more complicated, but the steps the electric field is still same. By applying the formula, the only thing we need to be careful is that we need to draw the electric field direction right, make it have the correct direction that the vector is pointing to on x and y components.

We then calculated electric field along and from a uniformly charged. We applied calculus and integration to solve it. This is the data calculated on instrustor's laptop.

Same problem, this picture is what we calculated on our laptop. The result has differences comparing to instructor's calculation, and the picture i take is not clear enough.

We derive a more general form of calculation for the electric field by integration for non-uniform distribution charged particles or system. It is similiar to calculate the moment of inertia. To express dQ, we apply line charge density, area charge density and volum charge density.