Drift speed formula requires current value

Steps:

• Calculate cross-sectional area: diameter = 0.42 mm = 4.2 × 10^{-4} m, radius = 2.1 × 10^{-4} m, A = π r² ≈ 1.38 × 10^{-7} m².
• Use drift speed formula: v_d = I / (n e A), where n = 8.0 × 10^{28} m^{-3}, e = 1.6 × 10^{-19} C.
• Current I is not provided in the question.
• Without I, v_d cannot be computed numerically.

Not enough information.

Final answer: Not enough information.