Will the magnitude of electric/magnetic force reduce if an non-magnetic or neutrally charged body is kept in between two charges magnets? If we keep two magnets or two charges in a space and keep a glass block or anything which is neutrally charged (should be big enough so that apparently it would look like its obstructing)in betweeen those,will the magnitude of force reduce in this case compared to the force that should act when tha neutral thing is absent?
 A: No. Physical objects cannot block block the electric field created by the first charge at the position of the 2nd charge (the electric field in the region where the object is placed DOES change but the force on charge 2 depends on the electric field present at its own position)
The (net) electric force between 2 charges does decrease  however if the medium is changed from vacuum to air or water for example. This is because when a charge creates an external electric field in a medium, the electron clouds of the atoms/ molecules of the medium shift slightly in the opposite direction of the external electric field under the influence the electric force. This is called polarization and results in an internal electric field of the medium in the opposite direction of the external electric field, thereby weakening the net electric field and this electric force exerted at every point.
The strength of the induced electric field depends on polarizibilty of the material and Is measured by "electrical permittivity" ε of the material.
This decrease in net electric force due to induced electric fields is directly incorporated in the coulomb constant 1/4πε
