Drift vs. Diffusion - Some charged proteins have diffusion coefficient and are located at the entrance of a microchannel of length , well-approximated by a 1D channel. Because the proteins are charged, if we apply an external electric field across the channel, we expect the proteins to reach a terminal velocity of . We call the drift velocity of the protein. Let's discuss which transport method, drift or diffusion, is more efficient for transporting proteins across the entire channel. a) Use dimensional analysis to find the drift velocity at which the drift and diffusive motions are equally efficient. Hint: Find an expression for using the other variables of the system, by finding which arrangement (multiplication, division) results in the proper units. b) Next, establish when diffusion is more efficient than drift motion by finding the time required for both methods to transport the particles across the channel as a function of the variables of the system. Then find a relation between and . c) Compare your answers a) and b). Are they the same?