Magnetism and M...

Mark the correct difference between a permanent magnet and an electromagnet.

 Identify the incorrect statement from the following.

The temperature, at which a ferromagnetic material entirely loses its magnetic properties, is referred as

Why the applications of permanent magnet in the field of engineering are quite limited?

An electron ofcharge e moves in a circular orbit ofradius r around the nucleus at a frequency v. The magnetic moment associated with the orbital motion of the electron is 

Which one of the following statement is not correct about the magnetic field?

Assertion: Lenz's law violates the principle of conservation of energy.
Reason: Induced emf always opposes the change in magnetic flux responsible for its production. 

An electron in a circular orbit of radius $$0.05\ nm$$ performs $${ 10 }^{ 16 }$$ revolutions per second. The magnetic moment due to this rotation of electron is (in $${ Am }^{ 2 }$$):

The ratio of magnetic dipole moment of an electron of charge $$e$$ and mass $$m$$ in Bohr's orbit in hydrogen atom to its angular momentum is

Why is an electromagnet more advantageous?