Question

The current density (number of free electrons per m³) in metallic conductor is of the order of

• A. 10^28
• B. 10^25
• C. 10^15
• D. 10^21

Answer 1

Answer: (A)

10^28

Answer 2

The number density of free electrons in a metallic conductor (n) is calculated by dividing the mass density ($\rho$) by the molar mass (M) and multiplying by Avogadro's number ($N_A$), assuming one free electron per atom. For copper, this calculation yields approximately $8.5 \times 10^{28} \, \text{electrons/m}^3$, which is of the order of $10^{28}$.