Output, i.e., useful work done per minute = 5.4 x 108 J
Input i.e., heat absorbed per minute = 3.6 x 109 J
Efficiency = Output/Input = 5.4 x 108/3.6 x 109 = 0.15 = 0.15 x 100% = 15%
Heat energy wasted/minute
= Heat absorbed/minute - Useful work done /min.
= 3.6 x 109 - 5.4 x 108 = 109 (3.6 x 0.54 ) = 3.06 x 10-9 J.