Static Fields 2021

Students explore the effects of putting a point charge at various places inside, outside, and on the surface of a cubical Gaussian surface. The Mathematica worksheet or Sage activity shows the electric field due to the charge, then plots the the flux integrand on the top surface of the box, calculates the flux through the top of the box, and the value of the flux through the whole cube.

What students learn

• Students see that the integrand of the flux through a surface depends both on the distance of the charge from the surface and on the angle between the direction from the surface to the charge and the unit normal to the surface.
• Students verify the integral form of Gauss's law for examples of charges inside the cube, on the edges or vertices of the cube, and outside the cube.