fieldstrength

Field strength is a measure of the intensity of a field at a specific location. In physics, it is usually defined as the force per unit of a test quantity associated with the field. For an electric field, the strength E at a point is the force F exerted on a small test charge q divided by q, so E = F/q. This reflects how strongly the field would act on charges in the region.

The term is used across different fields with field-specific conventions. Electric field strength is commonly expressed in volts per meter (V/m). Magnetic fields are described by the magnetic flux density B, measured in tesla (T), or by magnetic field strength H, measured in amperes per meter (A/m); in some contexts “field strength” for magnetism refers to either of these quantities depending on convention. Gravitational field strength refers to the force per unit mass and is equivalent to acceleration; near Earth’s surface it is about 9.81 m/s^2, and in general g = GM/r^2 for a point mass M at distance r.

Related concepts include dielectric strength, the maximum electric field a dielectric material can withstand without breakdown. Field strength can vary in space, forming profiles that are important in the design of devices, insulation systems, and safety assessments.

Measurement and modeling are common approaches to determine field strength. Experimental methods use probes or sensors such as electric field meters and magnetometers, while theoretical methods solve field equations or run simulations based on sources and boundary conditions.