Question

A student plans to determine the resistivity of a specific type of metal. To do this, the student will use wires constructed of the metal with known dimensions that are connected to a variable power source. The potential difference across and the current through each wire are measured and the resistance of each is calculated. The resistance is used to determine the resistivity. Which of the following should be kept constant to ensure that the resistivity values are consistent, and why?

a. The potential difference across the wires, because then only the currents will be different.
b. The currents in the wires, because then only the resistances will be different.
c. The lengths of the wires, because the resistivity changes with length.
d. The temperature of the wires, because resistivity changes with temperature.

Answer 1

reviewing the different answers, the correct one is d

Step-by-step explanation:

In the experiment to determine the resistivity of the wires, the student should use the relationship

R = ρ L / A

ρ = R A/L

in the statement they indicate that the difference that potential and current are measured, calculating the resistances from Ohm's law

V = i R

R = V / i

As resistivity is a property of the material that depends on the temperature, great care must be taken that the resistors do not change the temperature during the experiment, as this alters the resistivity value.

When reviewing the different answers, the correct one is d