ANS:B - centrifugal pressure exerted by the liquid.

The driving force in the case of filtration by a centrifuge is the centrifugal force exerted by the rotation of the centrifuge. Here’s an explanation:

1. Centrifugal Force:
   • When a centrifuge rotates, it generates centrifugal force due to the circular motion of the liquid and solid particles within the centrifuge.
   • Centrifugal force acts radially outward from the center of rotation and pushes the liquid and solid particles towards the outer wall of the centrifuge.
2. Filtration Mechanism:
   • In a centrifuge, the suspension or slurry is fed into the rotating drum or vessel.
   • Centrifugal force causes the denser solid particles to move outward towards the drum's wall, forming a cake layer.
   • The liquid (filtrate) passes through the cake layer and is collected in the center or bottom of the centrifuge, depending on the design.
3. Driving Force:
   • The centrifugal force generated by the rotation of the centrifuge is the primary driving force that separates the solid particles from the liquid.
   • This force overcomes the gravitational force and other forces, causing the solid-liquid separation to occur.

Therefore, in centrifugal filtration, the driving force is the centrifugal force exerted by the rotation of the centrifuge, not the speed of the centrifuge itself, the centrifugal pressure exerted by the liquid, or the diameter of the vessel. The formation of a highly porous cake is a result of the filtration process under centrifugal force.