Definition:Efficiency (Physics)

Definition

Let $S$ be a system.

Definition 1

The efficiency of $S$ is defined as:

$\EE = \dfrac {E_O} {E_I} \times 100 \%$

where:

$E_I$ denotes the energy input to $S$ over a particular time interval $T$

$E_O$ denotes the energy output from $S$ over that same time interval $T$.

Definition 2

The efficiency of $S$ is defined as:

$\EE = \dfrac {W_L} {W_E} \times 100 \%$

where:

$W_L$ denotes the work done by the load of $S$

$W_E$ denotes the work done by the effort of $S$.

Also see

• Equivalence of Definitions of Efficiency (Physics)

• Results about efficiency in the context of physics can be found here.

Sources

• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): efficiency: 3.
• 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): machine
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): efficiency: 3.
• 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): machine