The retentivity of soft ferromagnetic materials like soft iron is low and that of hard ferromagnetic materials like steel is high. Still retentivity of soft iron is more than that if steel. Why is it so??????

Four long co-axial thin walled cylindrical conductor A, B, C and D have radii R. 2R 3R and 4R respectively. A and C carry current I and 31 respectively to plane of paper on the other hand, B and D carry and 41 respectively outward to plane of paper. Then 21

I need solution of these questions.............................Magnetic effect of current

A freely suspended iron rod does not point at N-S directions alwalys .why

 

 

What is magnetic entropy change? For my knowledge, I know entropy is randomness or disorder. So here that magnetic refers to the magnetic dipole moments?

Derive the relation between magnetic field intensity (H) and magnetization (M) for a magnetic material placed in a magnetizing field.