What is an Electrostatic Field?

An electrostatic field is an invisible field that surrounds electrically charged particles. This field can form around two objects in the same vicinity with different electrical charges, or to a single object that is electrically charged in respect to its surrounding environment. Once formed, the electrostatic field can exert a force on other electrically charged objects in the vicinity.

The electrostatic field is a vector field that is defined as the force per unit charge that a stationary point charge would encounter at a particular point in the field. The electrostatic field is symbolized in mathematical equations as a capital letter “E”. In addition, the electrostatic field is measured using the International System of Units (SI) unit of newtons per coulomb.

The direction of an electrostatic field is equivalent to the direction of the force it exerts on a positive point charge. A stationary positive charge will have an electrostatic field pointing radially outward from the charge. On the other hand, a negative charge will have an electrostatic field pointing radially in towards the charge.

If two oppositely charged objects are within the same vicinity, the lines will start on positive charges and end on negative charges. The direction of the lines at any point between the two objects tells the direction in which the force will act. If a charge is positive, it will experience a force in the same direction as the field. On the other hand, a negative charge within an electrostatic field will experience a force in the direction opposite of the field.

The concept of an electrostatic field involves many properties similar to the force of gravity. A point charge within a uniform electric field acts in a similar fashion as an object on which the force of gravity is acting. Thus, using projectile motion and kinematic equations also applies to a point charge within a uniform electrostatic field.

Gauss’s Law is a method of calculating electrostatic c fields. Essentially, if you have a solid conducting sphere with a net charge of Q, you are able to asses that the excess charge lies on the outside of the sphere. Thus, Gauss’s law claims that the electrostatic field inside the sphere is zero and the electrostatic field outside the sphere is the same as a point charge with a net charge of Q. This assumption makes calculating vector components of an electrostatic field far easier.