Suppose a prime mover rotates at a steady speed of 900 rpm at rated full load and rotates at a steady speed of 1000 rpm at no load. Assuming that no adjustments have been made to the governor speed control setting, what is the speed regulation of the prime mover expressed in per cent?

Correct Answer: Option B — 11.1%

Speed regulation is calculated as the difference between no-load speed and full-load speed, divided by the rated full-load speed, multiplied by 100. Here, (1000 - 900) / 900 equals 0.111, or 11.1%. This percentage defines the governor's response characteristic in maintaining engine speed across varying load conditions.