Electrostatic precipitators: Electrostatic precipitators are devices used to remove particles, such…
Physics20251.25 marksShort answer
Electrostatic precipitators: Electrostatic precipitators are devices used to remove particles, such as dust and ash, from a flowing gas using the force of an induced electrostatic charge. It consists of two sets of electrodes: positive and negative. The negative electrodes are in the form of a wire mesh, and the positive electrodes are plates. These electrodes are vertically placed and alternate to each other. High Direct Current (DC) voltage is fed to the discharge electrodes, generating a negative electric field around them. The gas-borne particles such as ash are ionised by the corona effect. When the polluted gas passes through the electric field, the particles become charged and are attracted to oppositely charged collector plates, where they adhere until they are removed.
If the medium between the mesh and the plates is filled with a dielectric medium of dielectric constant $K = 10$, what will happen to the efficiency of working of the device?
Figure 91
Answer
Answer
Official answer key
On introducing the dielectric between the mesh and plates, the electric field between the plates reduces. Hence, the ionisation of gas molecules/dust particles reduces and the efficiency of the device decreases.
