Answer:
Step-by-step explanation:
Part A:
The resistance of the rod can be calculated using Ohm's law:
R = V/I = 176 V / 4.0 A = 44 Ω
The resistance of a cylindrical conductor can be calculated using the formula:
R = ρL/A
where ρ is the resistivity of the material, L is the length of the rod, and A is the cross-sectional area of the rod. For a square cross-section, the area is given by A = (0.50 cm)^2 = 0.25 cm^2.
Substituting the given values, we get:
44 Ω = ρ (20 m) / 0.25 cm^2
Simplifying, we get:
ρ = (44 Ω x 0.25 cm^2) / (20 m) = 0.55 x 10^-6 Ω·m
Therefore, the resistivity of the material is 0.55 x 10^-6 Ω·m.
Part B:
Whether the material is a conductor, an insulator, or a semiconductor depends on its resistivity. A material with a resistivity less than about 10^-4 Ω·m is considered a conductor, while a material with a resistivity greater than about 10^8 Ω·m is considered an insulator. Materials with resistivities in between are considered semiconductors.
In this case, the resistivity of the material is 0.55 x 10^-6 Ω·m, which is much smaller than 10^-4 Ω·m. Therefore, the material is a conductor.