Lesson One : Waves and Energy
Electromagnetic waves are transverse waves and have all of the characteristics of mechanical waves: wavelength, period, frequency, amplitude (actually, both the electric and magnetic components of the wave have amplitudes), and velocity (the speed of light, given before).There is a simple equation relating the wavelength, frequency, and velocity of an electromagnetic wave:
c = wavelength × frequency
Since c is a constant (it doesn't change), this equation gives a relationship between the wavelength and frequency:
If the wavelength increases, the frequency must decrease.
If the wavelength decreases, the frequency must increase.
In addition, the energy of the wave is proportional to its wavelength. In general,
Waves with longer wavelength and lower frequency have lower energy.
Waves with shorter wavelengths and higher frequency have higher energy.
These crucial concepts form the basis of the electromagnetic spectrum, which we’ll see in more detail on the next page.