Question

Find the power, given energy E = 2J and current density J = x^2 varies from x = 0 and x = 1.

(a) 1/3

(b) 2/3

(c) 1

(d) 4/3

I have been asked this question in an internship interview.

This interesting question is from Stokes Theorem topic in section Vector Calculus of Electromagnetic Theory

Answer 1

Right option is (b) 2/3

The best I can explain: From Stoke’s theorem, we can calculate P = E X I = ∫ E. J ds

= 2∫ x^2 dx as x = 0->1. We get P = 2/3 units.