method of images

The "method of images" is a technique used in physics, particularly in electrostatics, to solve problems involving electric fields and forces. It's especially useful when dealing with conductors.1

The core idea is to replace a complex physical setup, like a charge near a conducting surface, with a simpler, fictitious arrangement of charges. This fictitious arrangement, called "images," creates an electric field that is identical to the original field outside the conductor. This allows physicists to calculate forces and fields without directly solving the complicated boundary conditions imposed by the conductor.1

For example, if a positive charge is placed near a grounded conducting sphere, the method of images replaces the sphere with a negative "image" charge located inside the sphere. The interaction between the original charge and this image charge then accurately represents the force on the original charge due to the conducting sphere.1