A bar of iron having magnetic moment 2 4 Am ^2 weighs 66 g . If the density of the material of the bar is 7700 ~kg / m ^3 , the intensity of magnetisation in Am ⁻¹ is

Step-by-step solution

The intensity of magnetization I is defined as the magnetic moment per unit volume, given by I = M/V . Given the magnetic moment M = 2.4 , Am ^2 , mass m = 66 , g = 66 10⁻³ , kg , and density = 7700 , kg/m ^3 , the volume is calculated as V = m/ . V = 66 10⁻³ 7700 = 66 7700 10⁻³ , m ^3 = 6 7 10⁻⁵ , m ^3 Substituting into the magnetization formula yields: I = 2.4 6 7 10⁻⁵ = 2.4 7 6 10^5 = 2.8 10^5 , Am ⁻¹ This result corresponds to option B .