Final answer:
If the four wires are made from the same material, their resistivity would be the same, but resistance can vary due to differences in length and cross-sectional area.
Step-by-step explanation:
The question pertains to the electrical properties of wires made from the same material. If the four wires in Figure 20.48 are made from the same material, we can infer that each wire would have the same electrical properties such as resistivity. When considering wire properties, two important factors are resistance and cross-sectional area.
Since resistance is directly proportional to the length of the wire and inversely proportional to the cross-sectional area (A), provided the temperature remains constant, the wire with the longest length would have the highest resistance, and the wire with the greatest cross-sectional area would have the lowest resistance. Another critical factor is the resistivity, which is a material-specific property and thus would be identical for all wires.
In summary, if the wires are made from the same material, resistivity would be the same for all, but differences in their length and cross-sectional area could lead to variations in electrical resistance.