How much pressure is developed when the volume is doubled according to fan law?

According to fan laws, specifically the affinity laws relating to the performance of fans, the relationship between airflow, pressure, and power can be well-defined. When the volume of airflow is doubled, the pressure developed by the fan is affected according to the square of the ratio of the volumes.

When airflow (volume) is doubled, you take the square of that ratio (which is 2 for doubling). Therefore, the pressure developed will be 2 squared, equating to 4 times the original pressure. This principle is fundamental in understanding how fans adjust their performance based on changes in airflow and the pressure required to move that air.

In this context, the correct answer reflects the application of these laws, indicating that when the volume is doubled, the resulting pressure is quadrupled, leading to the conclusion that the correct choice is indeed four times the original pressure.