A magnetizing field of 100 ~A / m produces a magnetic flux of 2.4 10⁻⁵ ~Wb in an iron bar of cross-sectional area 0.3 ~cm ^2 . The magnetic permeability of the iron bar in the SI unit is

Step-by-step solution

The correct option is (A). Concept: Magnetic induction B = A , The permeability is the ratio of magnetic induction and the magnetic field = B H . Therefore, permeability can be written as = AH Given values are, A =0.3 10⁻⁴ ~m ^2 and =2.4 10⁻⁵ ~Wb B= A = (2.4 10⁻⁴ ~Wb ) (0.3 10⁻⁴ ~m ^2 ) =0.8 ~Wb / m ^2 Therefore, = B H = 0.8 1000 =8 10⁻⁴