Electric Flux

1. Electric Flux Gauss’s Law Electric Field of Spheres Other Gaussian Surfaces Point Charges and Spheres

2. E A Flux is defined as the amount of an electric field passing perpendicularly through a surface. For an electric field passing perpendicular to a plane, it is…

3. A E A What if the electric field is not perpendicular? E θ A

4. E What if the surface is a closed surface? q

5. In general, Gauss’ Law states that for any imaginary closed surface Gauss’ law is always true but not always useful. Qinside is the charge inside the imaginary surface. F is the total flux through this surface. We use Gauss’ law to calculate E. Gauss’ law is easy to use if the electric field vector is perpendicular to the chosen surface.)

6. Rules for Conductors All excess charge within a conductor moves to its surface. The electric field inside the material that makes up a conductor is zero. Electric fields just outside the surface of a conductor are perpendicular to its surface. Gauss’s Law is usually the best way to find the electric field of a conductor.

7. r E Outside any Sphere The electric flux A sphere with total charge Q Q from Gauss’ Law An imaginary Gaussian surface The electric field

8. r E Outside any Spherical Shell The electric flux Q Gauss’ Law The electric field

9. R r E Inside any Spherical Shell The electric flux Q Gauss’ Law The electric field

10. En En For a cylinder or a plane, the principal is the same but the surface used changes Note that the end faces must be included unless the cylinder is infinitely long.

11. r E Outside a Conductor with a Point Charge Inside The electric flux Q Gauss’ Law q The electric field

12. R r E Inside a Conductor with a Point Charge Inside The electric flux Q Gauss’ Law q The electric field

13. r E Outside a Conductor with a Point Charge Outside The electric flux Q Gauss’ Law q The electric field

14. R r E Inside a Conductor with a Point Charge Outside (it works as a shield and lets no electric field inside its walls) The electric flux Q Gauss’ Law q The electric field

15. Electric Flux Gauss’s Law Electric Field of Spheres Other Gaussian Surfaces Point Charges and Spheres