Man's physical universe

xanabras

UNIT VII

SECTION 7

THE GENERATION AND RECEPTION OF ELECTRO-

MAGNETIC WAVES ARE THE FUNDAMENTAL PROBLEMS

OF THE RADIO

The real credit for everything that has been done in the field of wireless

belongs, as far as such fundamental credit can be definitely assigned to anyone,

to Professor Clerk Maxwell, who in 1864 carried out certain abstruse and remote

calculations in the field of magnetism and electricity. — Abraham

Flexner.

Introduction.

The majority of the great scientific

developments of today represent

the contributions of research men working in many different

laboratories throughout the world.

Each man adds his bit to the final

result, but few discoveries are outstanding in themselves. There are

usually a few pioneer discoveries of fundamentals upon which all

future work is based.

In this Section we shall study the basic principles

of the transmission and reception of electrical energy in

the form of

electromagnetic waves, upon which the modern radio is founded.

Maxwell Originated the Electromagnetic Theory of Light.

In 1864 Clerk Maxwell, the great English mathematical physicist,

reached the conclusion from his calculations that all forms of radiant

energy are nothing more or less than electromagnetic waves.

The "lines of force" studied in magnetism and in current electricity

are thought to exist for every electron. These "lines of force" represent

a convenient fiction to express the "field of influence." When

the electrons are in a regular position, the field of influence becomes

evident, as in the case of magnets, because of their ability to repel or

attract bodies surrounded by similar fields of influence. When electrons

are in no regular position with relation to each other, as is true

in nonmagnetized matter, fields of influence surrounding the electron

neutralize, rather than reinforce, each other.

When electrons move in

one direction, as in a current of electricity, there is a motion of these

fields of influence. Now, what would happen to the field of influence

if the electrons were to oscillate back and forth? According to Max-

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