Eroxl's NotesGraph
Electric Field

The electric field is a vector field representing the force experienced by a charged particle at a given point in space. Electric fields can be visualized graphically using electric field lines.

The magnitude and direction of the electric field at any point in space is determined by the strength of the charge generating the field and the distance from that charge. Mathematically, the electric field is given by:

  • Definitions
    • is the electric field vector at that point
    • is Coulomb's constant
    • and are the charges of the two particles interacting, measured in Coulomb
    • is the distance between the two particles, measured in meters

Notice how this equation resembles coulombs law this is because electric field is a pre-calculation for the force a particle would experience if it was placed at a point.

This pre-calculation can be used as follows

Where is the force experienced by the particle, is the charge of the particle being placed in the electric field, and is the electric field vector at that point.

Note

If there are multiple charges present, the total electric field at any point is found by summing the electric fields from each individual charge. This is known as superposition.

Direction

The direction of the electric field at any point is defined as the direction a positive charge would move if it were placed at that point. Therefore, the electric field lines always point away from positive charges and towards negative charges.

Units

The electric field is measured in Newtons per Coulomb (N/C). This means that for every coulomb of charge present at a given point, the electric field will exert a force of one newton.

Examples

A charge of is Placed 2 Meters away from Another Charge. What is the Electric Field at the Location of the Second Charge?

Two Charges Are Placed on the X-axis. One charge is and is Located at . The other charge is and is Located at . What is the Electric Field at ?

Two Charges Are Placed on the \x-y-plane. One charge is and is Located at . The other charge is and is Located at . What is the Electric Field at ?

9000 N/C4500 N/CEθ