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Why does magnet attract only some of the materials like iron why not plastic ? What is the absolute reason behind it?
Why does magnet attract only some of the materials like iron why not plastic ? What is the absolute reason behind it? (Ankit Gururani posted in facebook)
Answer:
The answer cannot be limited to a quick reply.
The cause of magnetism is revolution of electrons. A revolving electron acts like a tiny magnet just like a current carrying coil does. If the magnetic moments of all the electrons nullify the effect of each other, it is non magnetic else it is a magnetic substance.
A magnetic substance consists of atoms or molecules having a net magnetic dipole moment. When an external magnetic field is applied or another magnet is brought near, the magnetic dipole moments get aligned and this results in the attraction of the magnetic substance by the magnet.
When the magnetic substance have their dipole moments aligned, it is said to be magnetised.
Visit the following links for more information
- http://en.wikipedia.org/wiki/Magnetism
- http://www.ndt-ed.org/EducationResources/HighSchool/Magnetism/hs_mag_index.htm
How does dielectric constant depend on nature of medium?
How does dielectric constant depend on nature of medium?
Does this have any relation with free electrons and force between molecules?
-Vaanya Asked
Answer:
Dielectric Constant, also called relative permitivity of a medium depends on the electric susceptibility of it, the ease with electric flux lines can pass through it.
The susceptibility depend on molecular polarization, the electric dipole moment acquired per unit volume in an external electric field.
So, the thing to note is that, dielectric constant is a physical quantity measured as a comparison of the strength of electric field in vacuum to that inside the material.
Dielectric constant can be defined in terms of electrostatic force
Dielectric Constant can also be defined in terms of capacitance.
Please visit the following links for more information.