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If σ = 2 ℧/m, E = 10 V/m, the conduction current density is
5 A/m2
20 A/m2
40 A/m2
30 A/m2
20 A/m2
Given: Conductivity σ = 2 mho/m, Electric field intensity E = 10 V/m
Conductivity σ = 2 mho/m, Electric field intensity E = 10 V/m
Jc=σE
Identify the given parameters
The problem provides conductivity σ=2 mho/m and electric field intensity E=10 V/m.
σ=2,E=10
State the conduction current density formula
According to Ohm's law in point form, the conduction current density Jc is given by the product of conductivity and electric field intensity.
Jc=σE
Calculate the current density
Substitute the given values into the formula to find Jc.
Jc=2×10=20 A/m2
B is correct because multiplying the conductivity by the electric field intensity yields a conduction current density of 20 A/m2.
In electromagnetics, remember that J=σE is the microscopic form of Ohm's law, similar to V=IR in circuit analysis.