전류 I = nqv_d A에서 v_d = \dfrac{I}{nqA} 입니다.

1. 단면적 A: \displaystyle A = (1.0 \times 10^{-3}\,\text{m})^{2} = 1.0 \times 10^{-6}\,\text{m}^{2}

2. 전하 운반자 밀도 n: \displaystyle n = \left(\dfrac{\text{밀도}}{\text{몰 질량}}\right) \times N_{A} \times (\text{e-/atom})

\displaystyle n \approx \dfrac{2.7 \times 10^{6}\,\text{g/m}^{3}}{27.0\,\text{g/mol}} \times (6.0 \times 10^{23}\,\text{mol}^{-1}) \times 1 \approx 6.0 \times 10^{28}\,\text{m}^{-3}

3. 유동 속력 v_d:

\displaystyle v_d = \dfrac{5.0\text{A}} {(6.0 \times 10^{28}\,\text{m}^{-3})(1.6 \times 10^{-19}\,\text{C})(1.0 \times 10^{-6}\,\text{m}^{2})}

\displaystyle v_d \approx 5.2 \times 10^{-4}\,\text{m/s} = 0.52~\text{mm/s}