4.4

efficiency = useful energy output

                                                        total energy input

Version 1

Efficiency = Useful E_out / Total E_in x 100

Useful E_out = Useful Energy Out ( J )

Total E_in = Total Energy In ( J )

Efficiency = Efficiency ( % )

Version 2

Efficiency = Useful E_out / Total E_in

Useful E_out = Useful Energy Out ( J )

Total E_in = Total Energy In ( J )

Efficiency = Efficiency ( No Units; a number between 0 and 1 )