Ch. 22- A charged particle sets up an electric field (a vector quantity) in the surrounding space. If a second charged particle is located in that space, an electrostatic force acts on it due to the magnitude and direction of the field at its location- Electric field lines extend away from positive charge (where they originate) and toward negative charge (where they terminate).- If more than one charged particle sets up an electric field at a point, the net electric field is the vector sum of the individual electric fields—electric fields obey the superposition principle.- Because of the 1/z3 dependence, the field magnitude of an electric dipole decreases more rapidly with distance than the field magnitude of either of the individual charges forming the dipole, which depends on 1/r2 .- If charge q is positive, the force vector is in the same direction as the field vector. If charge q is negative, the force vector is in the opposite direction (the minus sign in the equation reverses the force vector from the field vector)- The electric field due to a continuous charge distribution is found by treating charge elements as point charges and then summing, via integration, the electric field vectors produced by all the charge elements to find the net vector.- e An electric dipole consists of two particles with charges of equal magnitude q but opposite sign, separated by a small distance d. Their electric dipole moment has magnitude qd and points from the negative charge to the positive charge. The magnitude of the electric field set up by thedipole at a distant point on the dipole axis (which runs through both charges)Ch. 23- The electric flux through a surface is the amount of electric field that pierces the surface. - The area vector for an area element (patch element) on a surface is a vector that is perpendicular to the element and has a magnitude equal to the area dA of the element.- Guass’ law relates the electric field at points on a (closed) Gaussian surface to the net charge enclosed by that surface.- An inward piercing field is negative flux. An outward piercing field is positive flux. A skimming field is zero flux.- An excess charge on an isolated conductor is located entirely on the outer surface of the conductor. - The internal electric field of a charged, isolated conductor is zero, and the external field (at nearby points) is perpendicular to the surface and has a magnitude that depends on the surface charge density- A shell of uniform charge attracts or repels a charged particle that is outside the shell as if all the shell’s charge were concentrated at the center of the shell.- If a charged particle is located inside a shell of uniform charge, there is no electrostatic force on the particle from the shell. Inside the shell, the field due to the shell is zeroCh. 24- The points on an equipotential surface all have the same electric potential. The work done on a test charge in moving it from one such surface to another is independent of the locations of the initial and final points on these surfaces and of the path that joins the points. The electric field is always directed perpendicularly to corresponding equipotential surfaces. - In a uniform field of magnitude E, the change in potential from a higher equipotential surface to a lower one, separated by distance delta x- A positively charged particle produces a positive electric potential. A negatively charged particle produces a negative electric potential.- For a continuous distribution of charge (over an extended object), the potential is found by (1) dividing the distribution into charge elements dq that can be treated as particles and then (2) summing the potential due to each element by integrating over the full distribution- In order to carry out the integration, dq is replaced with the product of either a linear charge density l and a length element (such as dx), or a surface charge density s and area element (such as dx dy). - In some cases where the charge is symmetrically distributed, a two-dimensional integration can be reduced to a one-dimensional integration- The component of in any direction is the negative of the rate at which the electric potential changes with distance in that direction.- The total potential energy of a system of particles is the sum of the potential energies for every pair of particles in the system.- An excess charge placed on a conductor will, in the equilibrium state, be located entirely on the outer surface of the conductor.- The entire conductor, including interior points, is at a uniform potential.- If an isolated charged conductor is placed in an external electric field, then at every internal point, the electric field due to the charge cancels the external electric field that otherwise would have been there. - Also, the net electric field at every point on the surface is perpendicular to the surface.Ch. 37- 1. The Relativity Postulate: The laws of physics are the same for observers in all inertial referenceframes. No one frame is preferred over any other.- 2. The Speed of Light Postulate: The speed of light in vacuum has the same value c in all directions and in all inertial reference frames.- The time interval between two events depends on how far apart they occur in both space and time; that is, their spatial and temporal separations are entangled.- When two events occur at the same location in an inertial reference frame, the time interval between them, measured in that frame, is called the proper time interval or the proper time. Measurements of the same time interval from any other inertial reference frame are always greater.- The length L0 of an object measured in the rest frame of the object is its proper length or rest length. Measurements of the length from any reference frame that is in relative motion parallel to that length are always less than the proper