Question I know that a gravitational sheild is not possible.Which essentially means that the GRAVITATIONAL FORCE BETWEEN 2 particles is unaffected by the prescence of ANYTHING that may be present In their vicinity.
Is this true for electric force?I have read that the force between 2 charges reduces by 1/k times the force in vaccum when placed in a dielectric of dielectric constant 'k'.Does the "force" here refer to the NET force on any one charge or to the electric force BETWEEN the 2 charges? Can the electric force between two charges be in any way affected by what is around them?
Answer One can argue whether the change in the electric force between two charged objects, when there is a dielectric substance placed between them, is either (1) an actual change in the force, or (2) the effect of the charged particles within that dielectric. The result is the same no matter what you claim is "really" happening -- the electrical attraction between the two charged objects is different from what it would be if there were no dielectric between the two.
The difference with gravity is this: there is no possibility of a similar "shield" for gravitational force. No matter what you place between two objects with mass, the warping of space caused by each of the two objects is the same. Thus, although it is not difficult to shield a charged object from electrical fields, it is impossible to do the same for objects with mass.
I'm not sure I answered your question, but I tried to give you a start on understanding what our universe is like. Feel free to ask a different follow-up question if I didn't give the information you were looking for.
