2. Property of space around a charged object that causes forces on other charged objects Electric Field

3. Measuring the Field Intensity of a Charged Object To determine the intensity of a field, use a test charge q’ at any given point from the object being tested. The test charge is a small positive particle. + The field can be determined by the effects on the test charge in different locations According to Coulombs Law the closer the test charge the stronger the force

4. + Field Intensity = E = is proportional to the force on the test charge and inversely proportional to the charge itself. This ratio is independent of the test charge. The direction is the direction of a positive (+) charge toward a negative (-) charge

5. + + - + + + Field Line Field Lines Represent the Intensity and Direction of the Electric Field Test Charge s

6. Unlike ChargesLike Charges

7. Direction of Electric Field The electric field direction is always directed away from positive source charges and towards negative source charges.

8. The density of electric field lines around these three objects reveals that the quantity of charge on C is greater than that on B which is greater than that on A. Electric Field Intensity The greater the number of electric field lines. The greater the field intensity.

9. 1. The closer together the lines of force, the stronger the electric field. 2. The directions of the electric field is tangent to the lines of force. 3. The electric field lines start at positive charges and end on negative charges. 4. The number of lines leaving or entering a charge is proportional to the magnitude of the charge.

10. Conductors and Electric Field Electric field is zero everywhere inside a charged conductor Any excess charge on an isolated conductor resides entirely on the surface of the conductor The electric field at the outer surface of a charged conductor is perpendicular to the surface Excess charge tends to accumulate at sharp points, or locations of greatest curvature, on charged conductors. The places of highest charge accumulation are where the electric field from the conductor is the largest

11. Gauss’s Law for Electric Fields The net number of electric field lines passing through an imaginary surface is proportional to the amount of net charge enclosed within that surface