Chapter 6: Gauss's Law Flashcards
What is the electric flux?
The net number of field lines passing through a box (total enclosed charge divided by a constant).
What is the direction of the electric flux through the surface of a box containing net positive charge?
Positive net flux through the surface (points outside the box).
What is the direction of the electric flux through the surface of a box containing net negative charge?
Negative net flux through the surface (points into the box).
What is the direction of the electric flux through the surface of a box containing an equal amount of positive and negative charges?
There is no net flux through the surface (zero flux).
What is the direction of the electric flux through the surface of a box containing no charges?
There is no net flux through the surface (zero flux).
What is the direction of the electric flux through the surface of a box containing no net charge with a nearby positive charge outside the box?
There is no net flux through the surface (zero flux). Only charges inside the box contribute to a net flux through the surface of the box.
What do we call the imaginary box we draw to measure the flux?
A Gaussian Surface.
Where does the area vector A point?
The area vector A points perpendicularly out from a surface.
Where does the electric field vector E point?
Directly away from positive charges and directly towards negative charges.
We can use the non-integral form of Gauss’s Law under which two conditions?
- The shape of the box you chose results in a constant angle between the electric field vector E and the area vector A on each surface of the box.
- The electric field E has a constant value on each surface of the box.
What is the angle phi equal to?
The angle phi is the angle between the electric field vector E and the area vector A.
What is Q(enc) equal to?
The total charge inside your imaginary box (Gaussian Surface).
What is the best choice of Gaussian Surface to surround a spherical charge distribution, such as a ball?
A sphere centered on the charge distribution.
What is the best choice of Gaussian Surface to surround a cylindrical charge distribution, such as a wire or bar?
A cylinder with the same center axis as the charge distribution.
The enclosed charge Q(enc) must be written in terms of which three variables, each of which is multiplied by either the length, area, or volume?
The linear charge density lambda, the surface charge density sigma, and the volume charge density rho.
