In which situation will the lowest resistance occur?
A. thick wire and high temperature
B. thin wire and high temperature
C.thick wire and cold temperature
D.thin wire and low temperature
Question
Question
In which situation will the lowest resistance occur?
A. thick wire and high temperature
B. thin wire and high temperature
C.thick wire and cold temperature
D.thin wire and low temperature
C. Thick wire and cold temperature.
Explanation:
The resistance of a wire is given by: R = (ρL)/A
where ρ is the resistivity of the material, L is the length of the wire, A is the cross-sectional area of the wire.
From the formula, we see that the thicker the wire, the larger A, therefore the smaller the resistivity. so, a thick wire will have lower resistivity.
Moreover, the resistance of a wire increases with the temperature. In fact, high temperatures mean more motion of the atoms/electrons inside the wire, so more resistance to the flow of current through it. Therefore, colder temperature means lower resistance.
So, the correct option is thick wire and cold temperature.