Size Reduction and Milling

In comminution equipment (such as hammer mills and roller mills), the actual thermodynamic energy efficiency of size reduction is typically:

Options:

• (A) Less than $1\%$ to $2\%$ (over $98\%$ of input energy is lost as heat, sound, and mechanical friction)
• (B) $80\%$ to $90\%$
• (C) $50\%$
• (D) $100\%$