Leaving Certificate Physics Practice Test 2026 – Complete Exam Prep Guide

Electric field strength is defined as the force on a small test charge divided by that charge: E = F/q. This means the force per unit charge a test charge would feel in a region of space is exactly the field strength. Since F = qE, dividing by q gives F/q = E, so the quantity describing how strong the field is matches the phrase “force per unit charge.” The electric field itself describes the region and direction of the force, while potential difference (voltage) is energy per unit charge and the volt is its unit. The field strength focuses on the magnitude of the force per unit charge, which is why it’s the correct match.