Liquid helium is stored at its boiling-point temperature of 4.2k
in a spherical container (r = 0.404 m). the container isa
perfect blackbody radiator. the container is surrounded by
aspherical shield whose temperature is 86.8 k. a vacuum exists
inthe space between the container and shield. the latent heat
ofvaporization for helium is 2.1 x 104 j/kg. what mass
ofliquid helium boils away through the venting valve in
15.5hours?

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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.