Question

Calculate the magnetic energy when the magnetic intensity in air is given as 14.2 units(in 10^-4 order)

(a) 1.26

(b) 2.61

(c) 6.12

(d) 1.62

I got this question by my college professor while I was bunking the class.

Asked question is from Magnostatic Energy in chapter Magnetostics of Electromagnetic Theory

Answer 1

The correct option is (a) 1.26

Easiest explanation: The magnetic energy is given by E = 0.5 μ H^2. Put H = 14.2 and in air μ = 4π x 10^-7, we get E = 0.5 x 4π x 10^-7 x 14.2^2 = 1.26 x 10^-4 units.