Pest Control Aircraft Pilot Practice Test

To double the liquid output of spray nozzles, what must happen to the spray pressure?

1. It must double

2. It must quadruple

3. It must remain the same

4. It must increase by 50%

The correct answer is: It must quadruple

To effectively double the liquid output of spray nozzles, the spray pressure must be increased by a factor of four. This relationship is grounded in the physics of fluid dynamics, specifically the principle that flow rate through a nozzle is proportional to the square root of the pressure difference driving the fluid. When pressure is increased, the flow rate through the nozzles increases, but it's not a linear relationship. The formula indicating this relationship suggests that flow rate increases with the square root of pressure. Therefore, if one wants to double the output of the spray nozzles, it is necessary to increase the pressure four times (since the square root of four is two). This highlights the importance of understanding the relationship between pressure and flow in spray applications, as a misunderstanding can lead to inadequate pest control performance or inefficiency in pesticide application. This understanding also clarifies why other options do not lead to doubling the liquid output effectively. Increasing the pressure to double or keep it the same would not achieve the desired doubling of the output. A 50% increase would similarly fall short of the required increase in pressure necessary to achieve that doubling effect.