The left end of a long glass rod 9.00 cm in diameter, with an index of refraction 1.61, is ground and polished to a convex hemispherical surface with a radius of 4.50 cm. An object in the form of an arrow 1.55 mm tall, at right angles to the axis of the rod, is located on the axis 24.0 cm to the left of the vertex of the convex surface.(a) Find the position of the image of the arrow formed by paraxial rays incident on the convex surface.(b) Find the height of the image formed by paraxial rays incident on the convex surface.(c) Is the image erect or inverted?

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 -