A wire of length and radius carries a steady current of when a potential difference…

PHYSICS · Single correct · CBSE · Physics · Current Electricity · Current Electricity

Problem

A wire of length

2.0\,\text{m}

and radius

1.0\,\text{mm}

carries a steady current of

5.0\,\text{A}

when a potential difference of

4.0\,\text{V}

is applied across its ends. If the free-electron number density in the wire is

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

and

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

, the electron mobility in the wire is nearly (a)

2.0\times10^{-4}\,\text{m}^2\,\text{V}^{-1}\,\text{s}^{-1}

(b)

6.2\times10^{-4}\,\text{m}^2\,\text{V}^{-1}\,\text{s}^{-1}

(c)

6.2\times10^{-5}\,\text{m}^2\,\text{V}^{-1}\,\text{s}^{-1}

(d)

3.1\times10^{-5}\,\text{m}^2\,\text{V}^{-1}\,\text{s}^{-1}