Heat engine uses thermal energy flowing from a heat source that is 225 k to a cold sink that is 50 k. what is the approximate efficiency of the heat engine?

77.8 %

Explanation:

The efficiency of a heat engine is given by:

where is the temperature of the cold sink and is the temperature of the heat source. In this problem,

so the efficiency is

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.

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