A Carnot engine takes in heat at a temperature of 790 K and releases heat to a reservoir at a temperature of 470 K. What is its efficiency?

1280 kilometers :D

Explanation:

790 K ' 470 K = 1280 KM (KILOMETERS)

real, smaller and upside-down.   so the answer should be b.

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.