Question

At the same temperature, two wires made of pure copper have different resistances. The same voltage is applied at the ends of each wire. The wires may differ in_____________.

a. length.b. cross-sectional area.c. resistivity.d. amount of electric current passing through them

Answer 1

a) length b) cross-sectional area

Step-by-step explanation:

• The resistance of a wire, assumed to be an homogeneous one, of a resistivity ρ, length L and cross-sectional area A, is given by the following expression:

`R = \rho * (L)/(A)`

• At the same time, the current flowing through the resistor, is related to the voltage applied at the ends of the wire, by Ohm's Law, as follows:

`I = (V)/(R)`

• So, for a given voltage, the current is proportional to the voltage, being the proportionality constant the resistance of the resistor.
• So, if the material of both resistances is the same, the wires can differ in the length L and / or in the cross-sectional area A.

Answer 2

length, cross-sectional area, and the amount of electric current passing through them

Step-by-step explanation: