13) Electric Fields

Electric Charges Create an Electric Field

• An electric field is produced around any electrically charged object.

• The strength of the electric field increases as you get closer to the charged object and decreases as you move away.

• Electric fields can be visually represented using field lines:

  • Field lines originate from positive charges and terminate at negative charges.

  • The lines are always perpendicular to the surface of the charged object.

  • The density of the lines indicates the strength of the electric field; closer lines signify a stronger field, while farther lines indicate a weaker field.

Charged Objects in an Electric Field Feel a Force

• When a charged object is placed in the electric field of another charged object, it experiences a force.

• This force results in either attraction or repulsion, depending on the charges involved.

• The force arises from the interaction between the electric fields of the charged objects.

• The strength of the force on an object is related to the strength of the electric field it occupies.

• As the distance between charged objects increases, the strength of the electric field decreases, resulting in a smaller force between the objects.

Sparking Can Be Explained by Electric Fields

• Sparks occur when there is a sufficiently high potential difference between a charged object and the earth (or an earthed object).

• A high potential difference leads to a strong electric field between the charged object and the earthed object.

• The strong electric field ionizes air particles by removing electrons, allowing the air, normally an insulator, to become conductive.

• This ionization enables current to flow through the air, creating a spark.