Show diagrammatically the behaviour of magnetic field lines in the presence of :
(i) Paramagnetic and
(ii) Diamagnetic substance, How does one explain this distinguishing feature ?

Explanation

Diamagnetic substances are those which have tendency to move from stronger to the weaker part of the external magnetic field. Electrons in an atom orbiting around nucleus possess orbital angular momentum. These electrons are equivalent to current carrying loop and thus possess orbital magnetic moment.Diamagnetic substance are ones in which resultant magnetic moment in an atom is zero.
(i)Deduce an expression for the frequency of revolution of a charged particle in a magnetic field and show that it is independent of velocity or energy of the particle.
(ii)Draw a schematic sketch of a cyclotron.Explain giving the essential details of its construction how it is used to accelerate the charged particles.