ANS:A - decreases

Production rate decreases with increased fineness, given a constant energy input to the size reduction machine. Here's why:

1. Energy Input and Fineness:
   • Achieving finer particle sizes in size reduction processes requires more energy input.
   • As the desired fineness increases, the energy required to break down the material into smaller particles also increases.
2. Impact on Production Rate:
   • With a fixed amount of energy input (e.g., from a crusher, grinder, or mill), the machine can achieve a certain production rate.
   • However, as the machine is required to achieve finer particle sizes (higher fineness), it needs to spend more energy on each particle.
   • This increased energy per particle reduces the overall production rate because the machine cannot process as many particles per unit of time compared to coarser grinding operations.
3. Practical Observations:
   • In industrial practice, operators often adjust the fineness of the output based on process requirements.
   • Increasing fineness typically leads to slower throughput or production rates due to the increased energy required per unit of material processed.