A loop of wire is initially held above a short solenoid. A constant counterclockwise (as viewed from above) current passes through the turns of the solenoid. The loop of wire is steadily lowered, eventually "encircling" the solenoid. Throughout this problem, when you answer questions about the direction of current, assume that you are viewing the wire loop from above, looking downward. What is the direction of the induced current in the loop when the loop is above the solenoid, moving downward

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 charge of an ion with 55 protons and 52 electrons is +3. the reason is because protons are positive, and there are three more than the amount of negative electrons.