EM Wave is a — wave

Light behaves as -- we can filter using polarized lenses

when directed at a substance light can knock electrons off of a substance (photo electric effect)

All parts of electromagnetic spectrom travel at the — speed

Wavelength Frequency, Energy. - Short wavelengths have — freq - long wavelengtas have — freq

low freq - — energy

- have longer (that readily bends around buildings)

- have clearer reception

-AM signals travel as changes in the — of radio waves

- have shorter wavelength

- poorer reception

EM signals travel as a change in frequency of radio waves

History of Radio/Telecommunication

electronical telegraph (1809)

constructed the first commercial electical telegraph in England

own version of electrical telegraph. Used in another side of Atlantic Ocean.

em waves propagate through free space

radio wave propagation

Sxperimented transmission and radiation of radio f energy and proposed for telecommunication of information

conventional telephone (1876)

wireless telegraphy within a a two mile (2mile) using water transmission

wireless system

-transmission of Voice over airwaves (1900)

1st application of radio in commercial, military and marine communications.

- started a company for development and propagation of radio com services and equipment.

-pictures moving w/ halftone shades (1st true television pictures 1925)

scan surrounding

sends narrow beam of micro

receive reflected signals

uses of visible light