Image below shows configurations of jars filled with water. Which option will work as an air filter?
Show Hint
In a bubbler-type filter, remember the simple rule: "In below, Out above". The air must enter below the liquid surface and exit from the air space above it.
Step 1: Understanding the Concept:
The question asks which setup will function as an air filter using water. This type of filter, known as a bubbler or wet scrubber, works by forcing the incoming air to pass through a liquid (water). The water traps particulates (like dust and pollen) from the air, and the cleaned air exits.
Step 2: Key Formula or Approach:
For the device to work as a filter, two conditions must be met:
1. The "Air IN" tube must deliver the dirty air to a point \textit{below} the surface of the water, forcing it to bubble up.
2. The "Outlet" tube must draw the cleaned air from the space \textit{above} the surface of the water, to avoid drawing water out with the air.
Step 3: Detailed Explanation:
Let's analyze each configuration based on these two principles:
(A) The "Air IN" tube extends below the water level. The "Outlet" tube is positioned above the water level. When air is pushed in, it will bubble through the water (getting filtered) and the clean air will accumulate at the top to be drawn out through the outlet. This configuration will work correctly.
(B) The "Air IN" tube ends above the water level. The incoming air will simply flow over the water and exit through the outlet without being filtered. This configuration will not work.
(C) The "Air IN" tube is above the water, and the "Outlet" tube is below the water. This setup is incorrect and would likely siphon water out if suction is applied to the outlet. It will not filter the air.
(D) Both the "Air IN" and "Outlet" tubes are below the water level. This would cause water to be pushed out of the outlet along with the air, and it would not function properly as an air filter.
Step 4: Final Answer:
Only the configuration in option (A) correctly forces the inlet air to bubble through the water and allows the cleaned air to be extracted from above the water, thus functioning as an air filter.
