Efficiency Of Carnot Engine 1 T Sink T Source — the NEET Physics formula with its derivation, variables, validity constraints and worked solver.
Efficiency of Carnot Engine (η = 1 - T sink/T source) Applies to ideal reversible heat engines (Carnot engines) operating between two distinct thermal reservoirs. Sets the theoretical upper limit for the efficiency of any real heat engine. Define thermal efficiency as work done divided by heat absorbed: = W / Q in . Express work as the difference between heat absorbed and heat rejected: W = Q in - Q out . For a reversible Carnot cycle, the ratio of heat transfer equals the ratio of absolute temperatures: Q out / Q in = T sink / T source . Substitute to get = 1 - (Q out / Q in ) = 1 - (T sink / T source ). Temperatures must be in absolute scale (Kelvin). T source must be greater than or equal to T sink. T sink cannot be 0 K in practice (Third Law of Thermodynamics). Using Celsius or Fahrenheit instead of Kelvin for temperatures. Assuming efficiency can reach 100% (requires T sink = 0 K). Confusing the Carnot efficiency (theoretical maximum) with the actual efficiency of a real engine.