All these sentences are true.
<h3><u>Explanation</u>:</h3>
The resistance of a wire varies directly with the length of the conducting wire and varies inversely with the cross sectional area of the conductor.
The formula is given by R = ρ L/A.
So the longer the wire, the more the resistance. The thinner the wire, the more the resistance.
Now, the resistance of a conductor depends with temperature as
R =R(ref)[1 + α{T - T(ref)}]
As the conductors have a positive value for α, so the resistance of conductors will increase with increase in temperature.
