Lecture 11. E. Electromagnetic Radiation

Electromagnetic (EM) radiation is a propagating wave of oscillating ELECTRIC (E) and MAGNETIC fields, which moves at the speed of light.

A changing E field produces a B field, and vice versa. Hence, an EM wave is self-sustaining -- it "bootstraps" along, as in "pulling oneself up by one's boot straps!"

We'll only consider the E field for now, out of simplicity.

Sometimes EM radiation acts like a particle or PHOTON: collides like a billiard ball

Sometimes EM radiation acts like a WAVE: reflects, refracts, etc.

We describe an EM radiation in terms of wavelength, , or frequency, f

One thing the book does not emphasize enough, I think:

Of the EM waves we see as light, red has a longer wavelength than blue

We should combine all this info. in one place:
CATEGORY
____________________
____________________
____________________
____________________
____________________
____________________
HIGHER ENERGY
____________________
____________________
____________________
____________________
____________________
____________________
LOWER ENERGY
____________________
____________________
____________________
____________________
____________________
____________________

The text (fig. 4.5 & table 4.1) lists characteristics of EM radiation across the spectrum -- wavelengths, frequencies, and temperatures of formation.

You shouldn't memorize any numbers with each spectral category, BUT YOU SHOULD BE ABLE to place the categories in the correct ORDER according to energy, wavelength, frequency, or temperature.

If you know the order in one category, you can move between them if you understand this table above!