Question

Why the efficiency of heat engine is always less than 100%​

Answer 1

because some waste heat is always produced produced in a heat engine.

Step-by-step explanation:

the fraction of heat input that is converted to a net work output is a measure of the performance of the heat engine and is called the thermal efficiency.Since the machine does not contain a source of energy ,nor can it store energy ,from this conversation of energy the power output of machine can never be greater than its input,so efficiency can be less than 100%.

Answer 2

Step-by-step explanation:

The efficiency of heat engine is always less than 100% most of the times because of waste energy in form of heat.

• Different forms of heating occurs during the working of an engine
• As the mechanical workings of the engine sets in motion, heat is generated.
• One of the most common type of the heat is the frictional heating.
• Therefore, as energy is transformed from one form to another, some are lost as heat.
• In this regard, the efficiency of the engine suffers.