Question

P	Q	R
Magnets	Magnetic Substance	Non Magnetic Substance

A ring made up of copper and nickel can be placed in which group as shown in table ?

• A. P
• B. Q
• C. R
• D. Either Q or P

Answer 1

The correct option is B Q

$Ferromagnetic$ materials have a large, positive susceptibility to an external magnetic field. They exhibit a strong attraction to magnetic fields and are able to retain their magnetic properties after the external field has been removed. Ferromagnetic materials have some unpaired electrons so their atoms have a net magnetic moment. They get their strong magnetic properties due to the presence of magnetic domains. In these domains, large numbers of atom's moments (10¹² to 10¹⁵) are aligned parallel so that the magnetic force within the domain is strong. When a ferromagnetic material is in the unmagnetized state, the domains are nearly randomly organized and the net magnetic field for the part as a whole is zero. When a magnetizing force is applied, the domains become aligned to produce a strong magnetic field within the part. Iron, nickel, copper and cobalt are examples of ferromagnetic materials. Components with these materials are commonly inspected using the magnetic particle method.