The electrofilter consists of a long metal tube and a thread directed along the axis. A potential difference V is created between them. Air with dust is passed through the pipe.
a. To which electrode — to the thread or to the pipe — are dust particles attracted?
b. What is the force acting on a speck of dust with a dielectric constant of ε2, if the force acting on a speck of dust of the same radius, but with a dielectric constant of ε1, is equal to F1? Both motes of dust are equally distant from the filament.
c. How does the force of attraction depend on the potential difference? from the distance to the thread?
d. How many times is the force acting on a speck of dust of radius R greater than the force acting on a speck of dust of radius r < R? The dielectric permittivity of the dust particles is the same, and they are at the same distance from the filament.