An argon laser (λ = 5.0×102nm) shines down a silica glass fiber-optic cable with index of refraction 1.46. what is the speed of the laser light, cf , in the cable? select one of the following:
(a) 1.5 × 108 m s
(b) 2.1 × 108 m s
(c) 3.0 × 108 m s
(d) 4.4 × 108 m

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 answer is a 0.64 volts