Ferromagnetism

Q. What is the equation for magnetic forces?

Q.

Ferromagnetism is different from paramagnetism because

1. The atoms of a ferromagnetic material have net dipole moment whereas that of paramagnetic materials don’t.

2. Ferromagnetic material gets attracted to stronger field whereas paramagnetic materials don’t.

3. Ferromagnetic material gets attracted to weaker field whereas paramagnetic materials don’t.

4. Ferromagnetic materials form domains whereas paramagnetic materials don’t.

Q. When temperature of a ferromagnetic material is decreased to $80\%$, what is the percentage change in its magnetic susceptibility?

1. $40\%$
2. $80\%$
3. $25\%$
4. $20\%$