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## Homework Statement

There's an engine connected to a battery with a copper wire.

ρ = 1.69x10^-8

n = 8.49*10^28 electrons/m^2

The diameter of the wire is 5mm. The lenght is 1m.

How long does it take for an electron to go from the battery to the engine if i = 100A?

## Homework Equations

## v_d = \frac{J}{ne} = \frac{i}{Ane} ##

## The Attempt at a Solution

I calculated ##v_d## with the equation I wrote above.

I know that the drift velocity could be considered constant. So I calculated t:

## x(t) = 1m = vt => t = 1/v_d ##

My only question is: why did he give me the resistivity!?

Is there something unclear to me?

Thank you