Step 1: Identify equipment for controlling particulate air pollution. Particulate air pollution refers to suspended solid or liquid particles in the air. Common equipment used to control these particles includes:
Electrostatic precipitator: Efficiently removes fine particles by applying an electrostatic charge to the particles and collecting them on oppositely charged plates.
Cyclone separator: Removes larger particulates by using centrifugal forces to separate particles from the air.
Gravity settler: Removes particles by allowing them to settle due to gravity, suitable for larger and heavier particulates.
Incinerator: Used for burning waste but not specifically for controlling particulate matter; it is designed for volume reduction of solid waste.
Step 2: Analyze the options.
(1) Electrostatic precipitator: Correct. Effective for controlling fine particulates.
(2) Cyclone separator: Correct. Used for controlling medium-to-large particulates.
(3) Gravity settler: Correct. Suitable for large particulates in industrial applications.
(4) Incinerator: Incorrect. It is primarily used for waste combustion, not particulate pollution control.
Length of the streets, in km, are shown on the network. The minimum distance travelled by the sweeping machine for completing the job of sweeping all the streets is ________ km. (rounded off to nearest integer)