Aproton is moved so that its electric potential energy increases from 2.0 × 10-18 j to 6.0 × 10-18 j. the magnitude of the charge on a proton is 1.602 × 10-19 c.

the electric potential difference through which the proton moved, to the nearest whole number, is

ΔE=QΔV
4e-18J = 1.602e-19C * V
V = 4e-18J/1.602e-19C = 25V

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 -

The reflection of the candle in the concave mirror formed an upside-down virtual image that is smaller than the candle.in other words. the answer is the third option, c