How is the strength of an electric field defined?

The strength of an electric field is defined as the force experienced by a unit positive charge in the field.

In more detail, the electric field is a region around a charged particle or object within which a force would be exerted on other charged particles or objects. The strength of this field is a measure of the force it would exert on a unit positive charge placed within the field. It is a vector quantity, meaning it has both magnitude (strength) and direction.

The strength of an electric field (E) is calculated by dividing the force (F) experienced by a small test charge (q) due to the field, by the magnitude of that test charge. This is represented by the equation E = F/q. The unit for electric field strength in the International System of Units (SI) is newtons per coulomb (N/C) or volts per metre (V/m).

The direction of the electric field at a point is the direction of the electric force that would act on a positive test charge placed at that point. The lines of an electric field diagram point in the direction a positive test charge would move if placed in the field.

The strength of the electric field is directly proportional to the quantity of charge on the object creating the field and inversely proportional to the square of the distance from the centre of the charge. This relationship is known as Coulomb's Law.

In summary, the strength of an electric field is a measure of the electric force per unit charge that a positive test charge would experience if placed within the field. It is a fundamental concept in the study of electromagnetism and plays a crucial role in understanding the behaviour of charged particles and their interactions.