The processes of removal of particles in a rapid sand filter with their description is given in the table.
| Process |
Description |
| $\text{(i)}$ Straining |
P:Removes only particles in the water large enough to get caught in the pores of the filter |
| $\text{(ii)}$ Sedimentation |
Q: Larger and heavier particles do not follow the fluid streamline around the sand grain and settle on the grain |
| $\text{(iii)}$ Interception |
R: Particles that do follow the streamline, but are too large and are caught because they brush up against the sand grains |
| $\text{(iv)}$ Diffusion |
S: Very small particles are experiencing Brownian motion and may collide with the sand grains by chance |
Select the correct match.
- $\text{i- S; ii-P; iii-Q; iv-R}$
- $\text{i-Q; ii-R; iii-S; iv-P}$
- $\text{i-R; ii- S; iii- P; iv-Q}$
- $\text{i-P; ii-Q; iii-R; iv-S}$
