NCEA Level 2 Physics Practice Exam 2025 – Complete Preparation Guide

Electric field strength is defined as the force experienced by a unit positive charge placed in the field. This means that if you were to take a positive test charge and place it within an electric field, the electric field strength quantifies the force that this charge would feel per coulomb of charge. It is measured in newtons per coulomb (N/C).

This definition is fundamental in understanding how electric fields interact with charges, as it allows us to calculate the force on any charge in the field based on the strength of the electric field and the magnitude of the charge itself. Thus, option A accurately captures the essence of electric field strength as it relates to how forces act on charges within an electric field.

In contrast, work done per unit charge relates to electric potential, energy stored in a field refers to the potential energy within the electric field, and charge per unit area typically describes surface charge density rather than electric fields themselves.