2. A point source of 60Co gamma rays emits equal numbers of monoenergetic photons of 1.17 MeV and 1.33 MeV, giving a flux density of 5.7 x 109 photons cm-2 sec-1 at a specified location. What is the energy flux density there, expressed in erg cm-2 sec-1 and in J m-2 min

answer;

d. are made mostly of liquid

explanation;

-the general   composition and structure planets includes; they have a thick gas and liquid layer covering a small,solid core. mostly the gases are hydrogen and helium atmosphere and layers of liquid hydrogen. for instance neptune and uranus are examples of the outer planets, they have a core covered by ice and ammonia.

-neptune's atmosphere is hydrogen and helium with a bit of methane so there is no oxygen to breath and the interior is made up of frozen water and ammonia with a rock and iron core. thus, there is no liquid water or solid surface to survive.