Assignments for E1-E6. Changes may be made as we progress. DateLectureProblems assignedProblem due date Jan 24Rel. test + E2E2B.1, E2B.3, E2B.5, E2B.8 Jan 29 Jan 25Lab = Electric charge Jan 26E3E3B.1,E3B.7Jan 31 Mon, Jan 29E3 Jan 30Lab = Voltage of the Van de Graaff Jan 31E4E4B.1,E4B.2, E4B.3Feb 5 Feb 1Lab = Ohm/s law Feb 2E5E5B.1, E5B.4, E5B.5Feb 7 Mon Feb 5E6E6B.2, E6B.4 E6B.5, E6B.9 Feb 8 Feb 6Series and parallel resistors Feb 7Review for E1-E6 Test. Feb 8Circuits lab Feb 9Review for E1-E6 Test. Feb 12Test E1-E6

We will not cover section E2.6 (pages 33-36) Electric charge labs and static electricity labs are due Problems on chapter E2 are due

Chapter E3 Electric Potential We will not cover section E2.6 (pages 33-36)

Defination of Electric Field Therefore Units of E are? Newtons/coulomb

A review Energy is the ability to do work –Work is exerting a force through a distance Potential energy is the energy an object has due to its position. Electrostatic potential energy is the energy a charge possesses due to its location.

Electric Potential (Φ) Units are joules/coulomb=volt is useful to us for two reasons. First it is a scalar quantity and this is easier to calculate than a vector quantity, second, it shows us the energy at any place in space, and this is always useful. The electrical potential energy of the charge The magnitude of the test charge

A volt If one joule of work is necessary to move and object from point A to point B, there is a potential difference of one volt between these points. If ten joules of work is necessary to move an object from point A to point B, there is a potential difference of ten volts between A and B. –V AB = 10 volts

Potential of a point charge This gives the potential at point P due to a charge q at point P. Superposition principle

Example of an equalpotential diagram There is 1 volt between each contour. The energy is the same at every place on each contour. No work is required to move a charge along an equalpotential surface. The regions where the equalpotential surfaces are closest are the regions of highest electric field This is where a spark would first jump.

Example of an equal potential diagram See figure E3.1 G H

The potential at any point is the work bring a 1 coulomb charge from infinity to that point.

Getting from E to Φ and back D is the downhill direction of the electric field and this is always perpendicular to the equalpotential surface. The bigger E is, the closer together the equalpotential surfaces are.

Equations for formula sheet Put the equations from table E3.1 on your formula sheet. These equations give the potential from: –A point charge –A line of charge –A sheet of charge

Sphere Fields Outside Surface Fields Inside Surface Q=total surface charge r= distance from sphere’s center =directly away from sphere’s center Q= total surface charge R= radius of sphere

Infinite Cylinder = charge per unit length on cylinder =potential at surface r=distance from cylinder’s axis R=radius of cylinder’s surface =directly away from cylinder’s central axis

Infinite Flat Surface charge per unit area on surface distance from surface potential at surface directly away from surface r

Electric Field Energy Density How much energy a volume of space contains (joules/m 3 )

Problems for Wednesday E3B.1, E3B.7