Lesson 6: Second Law of Thermodynamics Answers

Which observations correctly describe the second law of thermodynamics? Check all that apply.Thermal energy that is not used to do work is often released to the surroundings.Thermal energy flows from a cooler object to a warmer object.Thermal energy flows from a warmer object to a cooler object.Thermal energy is released as unusable energy by a heat engine, which is never 100 percent efficient.Thermal energy flows when two objects in contact have a temperature difference.

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Which best describes how the first and second laws of thermodynamics are related?

Which has the highest entropy?

Why does entropy increase over time? Check all that apply.Heat engines are not 100 percent efficient.The natural tendency of systems is to break down, from order to disorder.All energy added to a system is used to do work.Unusable thermal energy is lost to the surroundings.Entropy is a measure of the order of a system.

An engine has an energy input of 125 J, and 35 J of that energy is transformed into useful energy. What is the efficiency of the engine?