Problem Statement
Free electron density in copper = 8.5e28 m-3. Current = 2 A, area = 2e-6 m2. Find drift speed.
Key Concepts
Drift velocity, current
Relevant Formulas
I = n e A v_d
Step-by-Step Solution
v_d = I/(n e A) = 2/(8.5e28 x 1.6e-19 x 2e-6) = 2/27200 = 7.35e-5 m/s.
Final Answer
v_d = 7.35e-5 m/s
Tips and Tricks
Drift speed is tiny compared to thermal speed of electrons.
Common Mistakes
Always use SI units. Check energy conservation accounts for all forms.
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