Question

Compute the conductivity when the current density is 12 units and the electric field is 20 units. Also identify the nature of the material. (a) 1.67, dielectric (b) 1.67, conductor (c) 0.6, dielectric (d) 0.6, conductor This question was addressed to me in an interview. My question is taken from Continuity Equation topic in chapter Electric Fields in Material Space of Electromagnetic Theory Select the correct answer from above options Electromagnetic Theory questions and answers, Electromagnetic Theory questions pdf, Electromagnetic Theory question bank, Electromagnetic Theory questions and answers pdf, mcq on Electromagnetic Theory pdf,electromagnetic theory book pdf,electromagnetic theory pdf notes,electromagnetic theory lecture notes,electromagnetic theory of light,maxwell electromagnetic theory,electromagnetic theory proposed by,electromagnetic theory engineering physics,electromagnetic theory nptel

Answer 1

Correct answer is (c) 0.6, dielectric For explanation I would say: The current density is the product of conductivity and electric field intensity. J = σE. To get σ, put J = 12 and E = 20. σ = 12/20 = 0.6. Since the conductivity is less than unity, the material is a dielectric.