The formula for calculating electric field strength is given by

where $E$ represents the electric field strength, $F$ denotes the force, and $q$ is the charge.

To elaborate further, the electric field strength quantifies the force experienced by a unit positive charge within an electric field. It is a vector quantity, which means it possesses both magnitude and direction. The equation $E = \frac{F}{q}$ is derived from Coulomb’s law. This law states that the force between two charged objects is directly proportional to the product of their charges and inversely proportional to the square of the distance separating them.

In this formula:

• $E$ (electric field strength) is measured in newtons per coulomb (N/C) or volts per meter (V/m).
• $F$ (force) is measured in newtons (N).
• $q$ (charge) is measured in coulombs (C).

The direction of the electric field indicates the path a positive test charge would take when placed in the field.

When the charge $q$ is positive, both the electric field and the force act in the same direction. Conversely, if the charge is negative, the electric field and the force act in opposite directions. This behavior arises because electric field lines emanate from positive charges and converge towards negative charges.

It is crucial to understand that the electric field strength at a specific point in space can be determined by introducing a small positive test charge at that location and measuring the force exerted on it. The electric field strength is then calculated by dividing the measured force by the charge. This method allows us to assess the influence of an electric field on a charge without needing to know the characteristics of the charge generating the field.

In summary, the equation

enables us to calculate the electric field strength at a specific point in space, providing insight into the force that a unit positive charge would experience due to the electric field at that location.