A current of 2A flows through a wire of cross-sectional area 25 . 0...

The drift velocity is given by

${v}_{d} = \dfrac{I}{neA}$

$⇒ I = nAe{v}_{d} . . . ( i )$

The given data is

$I = 2AA = 25 \times {10}^{- 6}{m}^{2}n = 2 \times {10}^{28}e = 1 . 6 \times {10}^{- 19}C$

Substituting the given values in equation (i)

$2 = 2 \times {10}^{28} \times 25 \times {10}^{- 6} \times 1 .6 \times {10}^{- 19} \times {v}_{d} ⇒ {v}_{d} = \dfrac{2}{2 \times {10}^{28} \times 25 \times {10}^{- 6} \times 1 .6 \times {10}^{- 19}}$

$⇒ {v}_{d} = \dfrac{1}{25 \times 1 .6 \times 1000}m{s}^{- 1} = 25 \times {10}^{- 6}m{s}^{- 1}$