Forces between charges, or from electric fields

• draw forces on a sketch of E fields
• a fast charged particle gives an impulse to another charge

Electric fields created by charges or dipoles

• Electric field plots of three point charges using 'short arrows' to represent the field.
• Electric field of N charges along a line (Excel)
• Electric field and electric flux of a point charge (Excel)

Electric potential

• plot the potential from a point charge not at the origin by shifting coordinates
• calculate V from long charged rod; obtain E from V.
• build a 'wall' to protect against invading protons, using a fixed total charge
• calculate V f rom long charged rod and do a contour plot
• given E field, find potential difference
• use line integral to find potential difference
• contour plot of electric potential from two point charges
• integrate to obtain the potential at a point due to a charged rod
• shift coordinates to obtain 3D potential plot when charges are moved
• make a 3D contour plot for 3 charges; locate equilibrium points
• make a 3D contour plot for 3 charges; find where Ex and Ey are zero
• try to trap a charge inside a box with charges at the 8 corners

Capacitance, Dielectrics

• Plot the capacitance of concentric spheres as a function of outer radius.
• Concentric spheres partly filled with dielectric
• integrate 'through'' a dipole 'layer' to find the net potential difference from a dielectric

Resistors, DC Circuits

• analyze currents in resistors
• current flow in a slab resistor
• given some currents in a DC circuit, find the remaining ones
• given some potential differences in a DC circuit, find the others

RC circuits

• Use RC circuit to 'demodulate' an incoming signal and obtain the 'envelope'
• RC circuit as a filter for various frequencies
• Examine noise with a R-C circuit

Magnetic fields created by currents

• integrate to find the magnetic field of a circular current loop
• 3-D plot of magnetic field in a helmholtz coil arrangement
• if you are close enough to one side of a rectangular loop, it acts like an infinite wire
• use derivatives to find the maximum slope (inflection point) on the axis of a circular loop
• integrate using Biot-Savart law to find B due to half of a current loop
• 3D plot of magnetic field in and around helmholtz coils
• In a rectangular loop, how close to one side must you be for the wire to look 'infinite'
• Create a 'loose' solenoid' of 2, 3, and 5 coaxial current loops

Motion of charges in electric or magnetic fields

• path of a particle in E and B fields (path in any E, B, v combination)
• path of a drop of ink under E field in an ink-jet printer
• electrostatic precipitator

Faraday's law

• which pickup coil will be effective?
• Can you extract power with a pickup coil near a power line?
• Lawnmower spark from magnets moving past a coil (maple)
• Lawnmower spark from magnets moving past a coil (Excel)

Inductance

• Where is the sensitive area of an airport metal detector?
• R-L-C circuit behavior