Understanding Electric Fields: Properties, Laws, and Potential

The Electric Field

1. Properties of Electric Charges

  • Point load: dimensionless electrical body.
  • There are 2 kinds of charges in nature:
    • Positives: load acquired by the glass rubbed. Carry this burden of protons.
    • Negative: is the burden becomes amber, and carry it with electrons.
  • The charges repel and attract opposite sign.
  • The charge is conserved. In the electrification charge is not created, only passed a few bodies to others, so that the total charge remains constant.
  • The charge is quantized. It is represented as an integer multiple of an elementary charge.

2. Electrostatic Interaction. Coulomb’s Law

  • Coulomb’s Law: The value of the force with which attract or repel two point charges at rest is directly proportional to the product of these charges and inversely proportional to the square of the distance that separates them.

Electric field
or Electric field

  • Value of k: Electric field
  • Coulomb: The quantity of electric charge flowing through a conductor section for a sec when the current is one ampere.

3. Force Exerted on a Point Charge by a System of Point Charges. Superposition Principle

  • Superposition principle: If a load is simultaneously subjected to several independent forces, the resultant force is obtained by adding vectorially these forces.

Electric field

4. Electric Field

  • There is an electric field in a region of space if a test charge q at rest, placed in a pt in that region would experience an electric force
  • An electric field is determined by three elements:

5. Electric Field Strength

  • Vector field is defined Electric field
    or electric field strength at any pt as the electric force Electric field
    acting on a unit positive test charge placed at the pto.

Electric field
is measured in N / C

  • Field strength created by an isolated point charge:

Electric field

  • Field strength created by a system of point charges:

Electric field

6. Electric Field Lines

  • The electric field is represented graphically by the so-called field lines or lines of force, which have the same direction as the vector field of each pt.
  • Properties:
    • Are open, always leave positive charges or at infinity and end at infinity or negative charges.
    • The No lines leaving a positive or a negative charge entering must be proportional to the load.
    • The field lines can not intersect. Otherwise, the court pt 2 vectors exist different field.
    • If a field is uniform, the field lines are parallel lines.

7. Electric Potential

  • Potential: potential energy per unit charge.
  • Variation of electrical Ep between 2 pts A and B of an electric field:

Electric field

  • Potential difference between 2 pts of an electric field

Electric field
being Electric field

  • Conclusions:
    • The potential V is a scalar field because it is defined by a value in each pt of space.
    • The potential value of a pto depends on the load creating the field and the distance of the load pt
    • The electric potential created by a point charge takes the same value at all points which are equidistant from the charge Q.
    • There is widespread potential in a pt is given by:

Electric field

  • The sign of the potential coincides with the sign of the charge
  • The unit of potential in the SI is the Electric field
    and is called the volt (V), is defined as:
  • In un pto electric field there is the potential of one volt when a charge of one coulomb force in this pt has the Ep of July.
  • Potential difference in a uniform field:

Electric field

  • Implications:
  • If q is positive, D U is positive.
  • If q is negative, D U is negative.
  • These consequences are also valid for nonuniform fields.
  • Pto potential in a field created by a system of point charges:

Electric field

  • Electric potential energy associated with a system of point charges:

Electric field