Which particle would have the slowest rate of deposition?

round particle
very large particle
particle with sharp ends
particle with a high density

c) particle with sharp ends

Explanation:

Rate of deposition of a particle determines how fast a particle of given characteristics (size, shape etc) will settle onto a surface. This is explained in terms of the Stokes law, according to which the frictional force (F) or the Stokes drag acting between the particle and the medium is proportional to the particle radius (R), flow velocity (v) and viscosity (μ)

F =  6πμRv

The frictional force which is essentially offers resistance to the flow will be the highest for irregularly shaped particles particles in this case those with sharp ends. As a result, these particles would have the slowest rate of deposition.