Answer:
T = 2 T₀
Explanation:
To answer this question let's write the expression for electrical conductivity
σ = n e2 τ / m*
The relationship with resistivity is
ρ = 1 /σ
Whereby the resistance
R = ρ L / A = 1 /σ L / A
We see that there is no explicit relationship between time and resistance, there is only a dependence on the life time (τ) that depends on the properties of the material, not on its diameter or length.
As also the average velocity or electron velocity of electrons is constant, the time to cross 2 mm in length is twice as long as the time to cross a mm in length
T = 2 T₀
