Where does the fluid enter in a Rotameter?

In a Rotameter, the fluid enters from the bottom of the device. This configuration allows the fluid to flow upward through a tapered glass tube. As fluid flows upward, it lifts a float that rises or falls depending on the flow rate. The position of the float within the tapered tube correlates directly with the flow rate, allowing for precise measurement. This design is essential because the upward flow creates a differential pressure, ensuring that the float will be lifted appropriately according to the volume of fluid passing through the device. Thus, the correct answer is that the fluid enters from the bottom.