Question

The principle of working of Konimeter dust sampler is

• A. Thermal precipitation
• B. Gravity
• C. Inertia precipitation
• D. Optical method

Hint:

Think of a fast-moving car trying to make a sharp turn on an icy road.
The car (like the dust particle) continues straight due to inertia.
The Konimeter uses this same principle to "throw" the dust particles out of the airstream and onto the collecting slide.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
We need to identify the physical principle behind the operation of a Konimeter dust sampler.

Step 2: Detailed Explanation:
The Konimeter is a type of "spot" dust sampling instrument.
Its operation involves the following steps:
1. A spring-loaded piston is released, which rapidly draws a small, fixed volume of air (typically 5 cm\(^3\)) into the instrument.
2. This air is forced at very high velocity through a narrow nozzle or jet.
3. The high-speed jet of air is aimed directly at a glass slide coated with a sticky substance (like glycerin).
4. The airstream makes a sharp turn and flows away, but the dust particles, due to their

inertia, cannot make the turn.
They continue along their straight path and collide with, and stick to, the glass slide.
This principle of separating particles from a fluid stream by using their inertia is known as

inertial impaction or

inertial precipitation.
The other principles belong to different instruments: Thermal precipitation (Thermal Precipitator), Gravity (Gravimetric samplers), and Optical methods (Photometers).

Step 3: Final Answer:
The working principle of a Konimeter is inertia precipitation.
This corresponds to option (C).