Does a bar magnet have a field along it's equtorial line? if it does then how can it be equivalent to a solenoid because for a solenoid the magnetic field outside it is zero?

Thank you in advance

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.