225. The mechanical efficiency (ηm) of an I.C. engine is equal to (where I.P. = Indicated power, B.P. = Brake power and F.P. = Frictional power) September 13, 2025 by Admin I.P/B.P. B.P/I.P. B.P/F.P F.P./B.P. ✅ The correct answer is option B.
