Question

5. A current of 1:0 A exists in a copper wire of cross-section
1:0 mm. Assuming one free electron per atom calculate
the drift speed of the free electrons in the wire. The
density of copper is 9000 kg m .​

Answer 1

Answer:

7.3 × 10⁻⁵ m/s

Explanation:

Current I related to drift velocity vd is given by

I = n×e×A×|vd|

where n is the number density of atoms , e is the charge on electron, A is area of cross section.

gram atomic weight of Copper atom 63.5 ; number density of atoms  is given by

n= (6.0×10²³×9000)/(63.5×10⁻³)=8.5×10²⁸m⁻³

Hence , |vd |= I/(n×e×A)=1/8.5×10²⁸×1.602×10⁻¹⁹×10⁻⁶=7.3 × 10⁻⁵ m/s