Answer:
All these particles behaves like small magnets which is known as domains
Explanation:
As we know that iron is a ferromagnetic substance so in this type of ferromagnetic substance all the medium particles will behave like small magnets which is known as small domains.
These domains have their own magnetic field which is very weak but if all the domains will align in same direction then all domains will combined and give strong magnetic field.
So in general case when iron nail is placed at room temperature then all these domains are randomly arranged and they do not give any net magnetic field while if we place the iron nail in external magnetic field then in that case the domains will align itself and give strong magnetic field in the direction of external field.
This is known as magnetization
Answer:
A. large industrial refrigeration and air-conditioning systems
Explanation:
