Answer:
Explanation:
Current density J = i / A where i is current and A is cross sectional area
J = 5 / π x ( .1 x 10⁻² )²
= 1.6 x 10⁶ A / m²
b )
electric field applied E = V / l where V is potential difference and l is lemgth of rod
E = 75 / 1.5
= 50 v / m
c )
J = σ E
J is current density , σ is conductivity and E is electric field .
1.6 x 10⁶ = σ x 50
σ = 3.2 x 10⁴ Ω⁻¹ m⁻¹
Resistivity = 1 / σ
= 1 / 3.2 x 10⁴
= .3125 x 10⁻⁴
=3.125 x 10⁻⁵ Ω m
