Iowa Pesticide Applicator Practice Exam

How does increasing the nozzle pressure affect the flow rate of pesticide application?

1. It decreases the flow rate.

2. It doubles the flow rate.

3. It quadruples the flow rate.

4. It has no effect on the flow rate.

The correct answer is: It quadruples the flow rate.

Increasing the nozzle pressure significantly impacts the flow rate of pesticide application due to the relationship between pressure and flow. When pressure is increased at the nozzle, the flow rate of the pesticide also increases, and this relationship is generally expressed by the equation related to flow through an orifice or nozzle, which states that flow rate is proportional to the square root of the pressure. When you increase the nozzle pressure, the amount of pesticide that can be expelled increases, effectively allowing for more liquid to flow through the nozzle within a given time frame. Specifically, if you double the pressure, the flow rate does not simply double; instead, it can increase by a factor that relates to the square root of the pressure change, which often leads to significantly higher flow rates—potentially quadrupling under certain conditions. This principle underscores the physics of fluid dynamics where an increase in pressure results in a disproportionately higher flow rate. This understanding highlights the need for proper calibration and monitoring of pressure settings in pesticide application to achieve effective and efficient coverage while minimizing waste and potential environmental impact.