1. ELECTRIC FIELD Chapter 26-5

2. Electric Field Michael Faraday proposed the idea that an electric field exist at any position at is not time dependent, but happens instantaneously unlike Coulombs law involving forces Charges or mass create a field that is physical entity acting in the region around a charge. If a charge/mass is moved within the field, the field(s) are/is in contact. Therefore there is a instant interaction between the two.

3. Definition of Electric Field The ratio of the force on a charge to the charge in the field or test charge. It is not the ratio of the force to charge creating the field.

4. Field Model Electric field is a vector field, meaning it exists at every location point. The diagram may only show a few of the points. The electric field points in the same direction as the force’s direction on a positive test charge. The electric field only depends upon the source charge. Example Two points charges of different quantities http://www.cbu.edu/~jvarrian/applets/efield1/elefi_z.htm - http://www.cbu.edu/~jvarrian/applets/efield1/elefi_z.htm Moving Charge http://www.cco.caltech.edu/~phys1/java/phys1/MovingCharge/Movi ngCharge.html http://www.cco.caltech.edu/~phys1/java/phys1/MovingCharge/Movi ngCharge.html

5. Electric Field of a Point Charge

6. Examples of Electric Fields and Forces Note: The electric field direction is always the same direction of the force on a positive test charge. E ++++++++++++++ Find net E direction due to 3 charges at the center position indicated with dot. Find force direction on each charge

7. Example Electric Field Problem: Determine the net electric field at the corner of the square with the other three corners showing the quantities of the charges as indicated. s s +2q -q