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Diffraction and Refraction ofRadio Waves

Learning Objectives:

All- Explain what long-distancecomm nication depends on!"ost- Explain how the refraction anddiffraction of radiation can affectcomm nications!#ome- Explain the advantage of digitalradio in terms of lac$ of interference

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#tarter Loo$ at the list of important events in the

field of comm nication and tr% to matchthem p with their inventor!

Extension- tr% to p t them in chronologicalorder

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"atch the &nventors with the&nvention ' ( )redit

Event Inventor

A invention of the telephone * + glielmo "arconi

, invention of television ( ans )hristian Oersted

) invention of a code consisting of a series of dots and

dashes. Alexander +raham ,ell

D the first person to s ggest the existence ofelectromagnetic waves / ,ill +ates

E the first transmission and reception of radio waves 0 &sambard 1ingdom,r nel

2 the first radio transmission from )ornwall to3ewfo ndland 4 5ames )ler$ "axwell

+ the prod ction of the first cell 6 5ohn Logie ,aird

a leader in the world of comp ters 7 einrich ert8

& the b ilding of the first transatlantic cable 9 #am el "orse

5 discover% of the magnetic effect of an electric c rrent * Alessandro ;olta

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Answers A. ,6 )9

D4 E7 2*

+* / &0

5(

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Diffraction of Radio Waves When long-wave signals meet an

obstr ction< li$e a hill< the% are diffracted