I have learnt that in cases of electrostatic fields inside a dielectric of any source charge, the field is reduced by a factor of K( if K, the dielectric "constant", is taken everywhere to be same). But that means that if there is, say, a fixed (by non-electric forces) charge outside a randomly shaped dielectric block, then the fields experienced by our test charge inside the dielectric will be weaker (by a factor of K) than what it would have experienced had it been outside the dielectric. But should the fields of other charges outside the block be unaffected??
If this is so, we take two opposite charges in vacuum separated by a distance and a dielectric block in between them. The lines of force would be passing through the slab and vacuum both. If the fields outside are not affected than there would be a contradiction since the closed line integral of field wouldn't be zero.
But then how and why would the fields outside the dielectric be changed. The contribution of the induced dielectric charges should be zero at least in the idealised case where infinitely large plates (producing uniform fields) have a dielectric bock (smaller then the separation) between them??