(i) What is meant by a paramagnetic substance? State Curie’s law.
(ii) What is the value of magnetic susceptibility of Aluminium of its relative permeability is 1.000022?
(i)
Paramagnetic substance—These are those substances when placed in an external magnetic field, are feebly magnetised in the direction of magnetising field, e.g.—Al, Na, Pt etc.
Curie’s Law—The susceptibility of a paramagnetic substance varies inversely as the Kelvin temperature of the substance.
This is known as Curie’s Law.
(ii)
Given:
μr = 1.000022.
We know,
μr = 1 + Xm
1.000022 = 1 + xm
So, Xm = 0.000022
How much force per unit length acts on a long current carrying conductor X due to a current flowing through another similar conductor Y, kept parallel to it in vacuum ?
Use this equation to define an Ampere, the fundamental unit of current.
(i) Arrange all the seven types of electro-magnetic radiations in increasing order of their frequencies. (You must begin with a radiation with lowest frequency and end with the one having the highest frequency.)
(ii) State how electric vector E, magnetic vector B and velocity vector C are oriented in an electromagnetic wave.