A parallel-plate capacitor of capacitance 20 µF is fully charged by a
battery of 24 V. The battery is then disconnected. A dielectric slab of k = 4
is slipped between the two plates of the capacitor:
(a) Find the change in the potential energy of the capacitor.
(b) Does the potential energy increase or decrease? Explain

An  atom  (ours, not carroll's) consists of a positively charged  nucleus, surrounded by one or more negatively charged particles called  electrons. the positive charges equal the negative charges, so the atom has no overall charge; it is electrically neutral. most of an atom's mass is in its nucleus; the mass of an electron is only 1/1836 the mass of the lightest nucleus, that of hydrogen. although the nucleus is heavy, it is quite small compared with the overall size of an atom. the radius of a typical atom is around 0.1 to 0.25 nanometres (nm), whereas the radius of a nucleus is about 10-6  nm.  *  if an atom were enlarged to the size of the earth, its nucleus would be only 200 feet in diameter and could easily rest inside a small football stadium.read more on -

Is this a question of an answer

Answerigneous bedrock of the oceanic crust;

Despite their crazy structure, human bones are surprisingly good!