electric charge

Examples of electric charge in the following topics:

• Gauss's Law

  • Gauss's law is a law relating the distribution of electric charge to the resulting electric field.
  • Gauss's law, also known as Gauss's flux theorem, is a law relating the distribution of electric charge to the resulting electric field.
  • Note that since Coulomb's law only applies to stationary charges, there is no reason to expect Gauss's law to hold for moving charges based on this derivation alone.
  • In words, Gauss's law states that: The net outward normal electric flux through any closed surface is proportional to the total electric charge enclosed within that closed surface.
  • Each of these forms in turn can also be expressed two ways: In terms of a relation between the electric field E and the total electric charge, or in terms of the electric displacement field D and the free electric charge.

• Conductors and Fields in Static Equilibrium

  • In the presence of charge or an electric field, the charges in a conductor will redistribute until they reach static equilibrium.
  • If conductors are exposed to charge or an electric field, their internal charges will rearrange rapidly.
  • Negative charges in the conductor will align themselves towards the positive end of the electric field, leaving positive charges at the negative end of the field.
  • This occurrence is similar to that observed in a Faraday cage, which is an enclosure made of a conducting material that shields the inside from an external electric charge or field or shields the outside from an internal electric charge or field.
  • Describe behavior of charges in a conductor in the presence of charge or an electric field and under static equilibrium

• Static Electricity, Charge, and the Conservation of Charge

  • Electric charge is a physical property that is perpetually conserved in amount; it can build up in matter, which creates static electricity.
  • In physics, charge conservation is the principle that electric charge can neither be created nor destroyed.
  • The net quantity of electric charge, the amount of positive charge minus the amount of negative charge in the universe, is always conserved.
  • Static electricity is when an excess of electric charge collects on an object's surface.
  • Formulate rules that apply to the creation and the destruction of electric charge

• Electric Field from a Point Charge

  • A point charge creates an electric field that can be calculated using Coulomb's law.
  • The electric field of a point charge is, like any electric field, a vector field that represents the effect that the point charge has on other charges around it.
  • The electric field of a positively charged particle points radially away from the charge.
  • The electric field of a point charge is defined in radial coordinates.
  • The electric field of a point charge is symmetric with respect to the θdirection.

• Stress and Strain

  • A point charge creates an electric field that can be calculated using Coulomb's Law.
  • The electric field of a point charge is, like any electric field, a vector field that represents the effect that the point charge has on other charges around it.
  • The electric field of a positively charged particle points radially away from the charge.
  • The electric field of a point charge is defined in radial coordinates.
  • The electric field of a point charge is symmetric with respect to the θdirection.

• Electric Potential Due to a Point Charge

  • The electric potential of a point charge Q is given by $V=\frac{kQ}{r}$.
  • Recall that the electric potential is defined as the electric potential energy per unit charge
  • The electric potential at a point is equal to the electric potential energy (measured in joules) of any charged particle at that location divided by the charge (measured in coulombs) of the particle.
  • The electric potential due to a point charge is, thus, a case we need to consider.
  • Express the electric potential generated by a single point charge in a form of equation

• Energy Conservation

  • Energy is conserved in the movement of a charged particle through an electric field, as it is in every other physical situation.
  • Energy is conserved in the movement of a charged particle through an electric field, as it is in every other physical situation.
  • Given a stationary test charge in a certain location, an applied electric field will cause the charge to move to one end or the other, depending on the charge (positive test charges will move in the direction of the field; negative charges will move in the opposite direction).
  • The charge, +q, is moved down the electric field in the same way that the object, m, is moved down the hill.
  • Formulate energy conservation principle for a charged particle in an electric field

• Electric Fields and Conductors

  • Electric fields are found around electric charges and help determine the direction and magnitude of force the charge exerts on a nearby charged particle.
  • There is no electric field inside a charged conductor.
  • A charged conductor at electrostatic equilibrium will contain charges only on its outer surface and will have no net electric field within itself.
  • Charged surfaces align themselves perpendicularly relative to electric fields.
  • Lines around the positive charge represent the electric field it creates.

• Electric vs. Magnetic Forces

  • Force due to both electric and magnetic forces will influence the motion of charged particles.
  • Where F is the force vector, q is the charge, and E is the electric field vector.
  • This electric field may be established by a larger charge, Q, acting on the smaller charge q over a distance r so that:
  • A consequence of this is that the electric field may do work and a charge in a pure electric field will follow the tangent of an electric field line.
  • The electric field surrounding three different point charges: (a) A positive charge; (b) a negative charge of equal magnitude; (c) a larger negative charge.

• The Production of Electromagnetic Waves

  • Electromagnetic waves are the combination of electric and magnetic field waves produced by moving charges.
  • The creation of all electromagnetic waves begins with a charged particle.
  • This charged particle creates an electric field (which can exert a force on other nearby charged particles).
  • When it accelerates as part of an oscillatory motion, the charged particle creates ripples, or oscillations, in its electric field, and also produces a magnetic field (as predicted by Maxwell's equations).
  • Once in motion, the electric and magnetic fields created by a charged particle are self-perpetuating—time-dependent changes in one field (electric or magnetic) produce the other.