Answer Happy

Cell membranes, which are we will approximate as 5nm thick, are
also rich in molecules that transport electrically charged ions. If
the membrane were simply porous, you would have equal
concentrations of Na+ for example, inside and outside the cell,
whereas the concentration is actually very low inside. (Na+ is a
sodium atom that has lost an electron, and so has one more proton
than electrons. Mg2+ is a magnesium ion that has lost two
electrons.) Coulombs law gives the electric force between two
charges in a vacuum, where the constant k (=1/4pi eo) sets the
strength of the force. In a polarizable medium the constant k
changes, normally denoted by a change in . For example, in a
hydrocarbon medium, such as the lipid molecules that make up a cell
membrane, e=4eo
1. if the force between two separated electrons immersed in a
lipid layer is F, how large would the force be in a vacuum for the
same electrons with the same separation? A)2F B)4F C)F D)F/2
I know the answer is B
I just need explanations of why