If E1 = Eo Cos(w t) and E2 = Eo Cos(w t + theta) : a) Derive an expression for E = E1 +E2.

b) Plot E = E1 +E2 as a function of t (choose appropriate values of the unspecified quantities).

c) Plot the amplitude of E = E1 + E2 as a function of theta (choose appropriate values of the unspecified quantities).

d) What is the value of the amplitude when (1) theta =0 and (2) theta = 90 dɛypeso; (choose appropriate values of the unspecified quantities).

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 -