Why is it that is impossible to have a 100 percent efficiency?

Achieving 100 percent efficiency is impossible due to the inherent limitations imposed by the laws of thermodynamics, particularly the second law, which states that energy transformations always result in some energy being lost as waste heat. Additionally, real-world processes involve friction, resistance, and other forms of energy dissipation that prevent complete conversion of input energy into useful work. Even in idealized systems, factors such as material imperfections and external influences introduce inefficiencies. Thus, some energy is always lost in any real process, making 100 percent efficiency unattainable.