Most likely the atoms of that elements are compress. :)
<span>it will be changed by changing the medium of the wave</span>
To solve this problem we will apply the concepts related to Coulomb's law for which the Electrostatic Force is defined as,

Here,
k = Coulomb's constant
= Charge at each object
r = Distance between them
As the distance is doubled so,





Therefore the factor is 1/4
Choice-'a' is a slippery, misleading, ambiguous statement,
but it's less wrong than any of the other choices on this list.