223 notes

c=f l speed of light = c = 3x10⁸ m/s

see text FBS page 25 1 Hertz= (1/second)

F M radio (WFMT) f=98.7 Megahertz,

l= 3x10⁸m/s /98.7x10⁶ (1/sec)=3.04 meters

AM radio (WGN) f=720 kilohertz,

l=3x10⁸m/s /720x10³(1/sec)

l=417 meters

TV (channels2)- f = about 60 Megahertz, l= 5 meters

UHF (channel 70) f=800 Megahertz, l = .375 meters

Cell phones f= about 900 Megahertz, l=.333 meters

Satellite communication f= 1.3Gigahertz, l=0.23 m

(microwaves)

Infrared l=3200nm=3200x10^-9 m, f= 94 Terahertz =9.4x10¹³ Hz.

Visible l=400 (Blue) to 700(red) nanometers f=7.5x10¹⁴ to 4.28x10¹⁴ Hz

Ultraviolet l= shorter than 400nm, est 300nm f=10¹⁵Hz

Xrays l=0.1nm f=3x10¹⁸ Hz

Sunlight striking the earth’s atmosphere has a range of wavelengths from 3200nm (IR) down to 225nm (UV). The range from 225 to 320 is absorbed by the ozone layer. Wavelengths longer than 1100nm are usually absorbed by water in the atmosphere.