PHYSICAL QUANTITY

Efficiency: formulas and units of measurement

Efficiency: symbol η, unit %. Formulas and explanations for Mechanics, MCT and thermodynamics.

ηpercentage

KEY CONNECTIONS

Formulas

η = Apol / Azatr

η = Qpol / Qzatr

η = (Q₁ − Q₂) / Q₁

η = (T₁ − T₂) / T₁

NOTATION

: Efficiency is the proportion of useful energy used.
: Useful work is the part of the work expended that is used for its intended purpose.
: Work expended is all the work done by a system or mechanism.
: Useful heat is the part of the received heat used for its intended purpose.
: Wasted heat is the entire amount of heat transferred to the system.
: Heater heat is the energy received by the working fluid from the heater.
: The heat of the refrigerator is the energy given by the working fluid to the refrigerator.
: Heater temperature is the temperature of the hotter heat source.
: Refrigerator temperature is the temperature of a cooler heat source.

THEORY

PRACTICE

Topics in order: the concepts, quantities and formulas of a lesson with explanations and examples.

Statements, answer options and a detailed walkthrough for every topic of the course.

A 10-question check-up, exercises with answer checking, and saved progress.