The farady experiment is actually a pretty long one. So as not being in my course and beyond my historical scope. This post only covers essential edited out parts of the experiment that gave us modern definition of electric flux.
Around 1837 as in my knowledge through wikipedia. Michael Farady become very interested in static electric fields and effect of various insulating materials on these fields which led to his experiement.
His Experiement then essentially consisted of following steps:
- He had a pair of concentric metallic spheres constructed, the outer consisting of 2 hemisphere that can be clamped to each other. He also preapared shells of insulating material which would occupy the whole volume between the concentric spheres. He dismantled it and gave the inner sphere a given positive charge.
- The hemisphere were then clamped together around the charged sphere with about 2 cm of dielectric between them.
- The outer sphere was discharged by connecting it momentorily to the ground.
- The outer sphere was seperated carefully without disturbing the charge in the inner sphere. The negative induced charge in each of the sphere was measured.
Faraday found out that:
- The total charge on the outer sphere was equal in magnitude with the original charge of inner sphere and this was true regardless of dielectric kept in between them.
- So it was concluded that the charge underwent to some displacement which was named as electric flux, or displacement flux.
This experiments gave way to the definition of electric flux.