In gel electrophoresis, the mobility of a molecule in a particular gel matrix is defined as

In gel electrophoresis, the mobility μ of a molecule in a particular gel matrix is defined as μ = v₁/E, where v₁ is the terminal speed of the molecule and E is the applied electric field strength. In one case, a molecule has mobility 3.0 × 10⁻⁸ C·m/(N·s) and charge −12e. 

(a) Estimate the electric field that should be applied to give this molecule a terminal speed of 2.0 × 10⁻⁵ m/s. 

(b) How long does it take the molecule to move 2.0 cm through the gel? 

(c) Suppose the same molecule had a charge of −8e instead of −12e. Considering the forces exerted on the molecule, would its terminal speed be smaller or larger (for the same applied field)? Would its mobility be smaller or larger?