Question

Find the magnetic flux density B when E is given by 3sin y i + 4cos z j + ex k.

(a) ∫(4sin z i – ex j – 3cos y k)dt

(b) -∫(4sin z i – ex j – 3cos y k)dt

(c) ∫(4sin y i – ex j + 3cos y k)dt

(d) -∫(4sin y i + ex j + 3cos y k)dt

This question was posed to me in a job interview.

My question is from Magnetic Field Density in chapter Magnetostics of Electromagnetic Theory

Answer 1

Right option is (b) -∫(4sin z i – ex j – 3cos y k)dt

The explanation is: We know that Curl (E) = -dB/dt. The curl of E is (4sin z i – ex j – 3cos y k). To get B, integrate the -curl(E) with respect to time to get B = -∫(4sin z i – ex j – 3cos y k)dt.