Final answer:
The correct unit for mobility is (A/m²)/(V/m) and the correct unit for σ (sigma) is (A/m)/(V/m²).
Step-by-step explanation:
The correct unit for mobility (μ) is (A/m²)/(V/m). This unit represents the ratio of current density (A/m²) to electric field strength (V/m). It measures how easily charge carriers move in a material under the influence of an electric field. For example, if the mobility of electrons in a material is 0.5 (A/m²)/(V/m), it means that for every volt per meter of electric field, the electrons will move with a current density of 0.5 amperes per square meter.
On the other hand, the correct unit for σ (sigma) is (A/m)/(V/m²). This unit represents the conductivity of a material, which is the reciprocal of resistivity. It measures how well a material conducts electric current under the influence of an electric field. For example, if the conductivity of a material is 0.2 (A/m)/(V/m²), it means that the material has a resistivity of 5 (V/m²)/(A/m).