Physics

Problem

(Mobility from wire measurements) A copper wire of length

2.0\,\text{m}

and uniform radius

0.50\,\text{mm}

carries a steady current of

5.0\,\text{A}

when a potential difference of

0.40\,\text{V}

is maintained across its ends. The free-electron number density in copper may be taken as

8.4\times10^{28}\,\text{m}^{-3}

. Use

e = 1.6\times10^{-19}\,\text{C}

. (i) Find the magnitude of the electric field within the wire. (ii) Determine the drift velocity of the conduction electrons. (iii) Calculate the mobility of electrons in the copper sample under these conditions. (iv) Estimate the time taken by an electron to drift from one end of the wire to the other. a. Find the magnitude of the electric field within the wire. b. Determine the drift velocity of the conduction electrons. c. Calculate the mobility of electrons in the copper sample under these conditions. d. Estimate the time taken by an electron to drift from one end of the wire to the other.

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