________________
(b)
netic waves by using a spark oscillator and then succeeded in detecting them also. Text book of Physics (Part II), op.cit, pp.94, 95"From Maxwell's field equations connecting the electric and the magnetic fields vectors E and B the wave equation for electromagnetic waves emerged, showing that the disturbances in E and B can jointly propagate in the form of waves. It was also found that the velocity of these waves in space as calculated from the electric and magnetic parameters was exactly equal to the velocity of light - strongly suggesting that light is a form of electomagnetic waves. It should be noted that all these deductions were logically deduced using theory only from the brilliant formulation of electromagnetic field equations.
2. Experiment of Hertz
55
Although existance of the electromagnetic waves theoritically deduced, an experimental demonstration that such waves can be produced in laboratory remaind to be achieved. It is said that Maxwell himself was very much desirous of being a witness to such an achievement during his lifetime. Thirty two years after the propositon of electromagnetic field, equations of Maxwell, Hertz demonstrated production of such
waves in laboratory. (a) Ibid., pp. 98, 99 —
"Characteristics of Electromagnatic Waves “Electromagnetic waves have the following characteristics : (1) At regions far from the source the electric and the magnetic
field, vectors oscillate in the same phase. The directions of oscillations of the electric and the magnetic fields are mutually perpendicular; and are in a plane
prependicular to the direction of propagation of the wave. (3) These waves are non-mechanical and of transverse type.
Their velocity in free space (vacuum) is given by c= 3 x 108 ms? Light waves have the same velocity in vacuum as
experimentally measured, (5) The velocity of electromagnetic waves depends upon the
electromagnetic properties of that medium."
(2)
DAT U511 37061 -fiatok, 2003 C
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