In an electrostatic precipitator, what charge does the discharge electrode have?

In an electrostatic precipitator, the discharge electrode is indeed negatively charged. This negative charge plays a crucial role in the functioning of the device. When polluted air passes through the precipitator, particles within the air are attracted to the negatively charged discharge electrode. As the particles come into proximity, they receive a positive charge due to the transfer of electrons. This process, known as ionization, effectively charges the particles in such a way that they can be attracted to the positively charged collector plates.

The negatively charged discharge electrode creates an electric field that facilitates this process, allowing for efficient particle capture by the collector plates. This setup is essential for the effective removal of pollutants, as it maximizes the interaction between charged particles and the charged surfaces in the precipitator.

Other options suggest different charge configurations or behaviors of components in the system, which do not align with how electrostatic precipitators function. For instance, if the particles were positively charged or both electrodes were positively charged, this would hinder the attraction process essential for debris collection. Therefore, the correct understanding of the discharge electrode's charge being negative is pivotal to grasping the operational mechanism of electrostatic precipitators.