Observe the given figure and answer the following questions:

Arrange the given steps for purification of air, in proper sequence. 

A. Attachment of electrons to dust particles giving them a net negative charge.
B. Passage of dirty air with particulate matter at low velocity.
C. Attraction of charged dust particles to grounded collection plate.
D. Release of electrons from electrode wires at several thousand volts.

Choose the correct answer from the options given below:

B, D, A, C

The correct answer is Option (2) → B, D, A, C

B. Passage of dirty air with particulate matter at low velocity.

D. Release of electrons from electrode wires at several thousand volts.

A. Attachment of electrons to dust particles giving them a net negative charge.

C. Attraction of charged dust particles to grounded collection plate.

There are several ways of removing particulate matter; the most widely used of which is the electrostatic precipitator , which can remove over 99 per cent particulate matter present in the exhaust from a thermal power plant. It has electrode wires that are maintained at several thousand volts, which produce a corona that releases electrons. These electrons attach to dust particles giving them a net negative charge. The collecting plates are grounded and attract the charged dust particles. The velocity of air between the plates must be low enough to allow the dust to fall.