5.1: electromagnetic radiation

many types, each with different wavelengths and frequencies
frequency (ν): the number of waves that pass a fixed point in a second
- measured in Hz (waves/second, cycle/second, 1/s, s-1)
wavelength (λ): inversely related to frequency
- waves are measured in meters (m) or nanometers (1m = 109 nm); nm are usually used in the visible region
- measured from the peak of one wave to the peak of the next, or the trough of one wave to the trough of the next
light in the visible range (colors) is the only type of electromagnetic radiation that the human eye can detect

light is composed of electromagnetic radiation
- has wave-like properties and is characterized by wavelength, frequency, and speed
- dependent on electronic structure (how the formation of electrons in an atom is) and electromagnetic radiation
electromagnetic radiation travels in waves that have electric fields and magnetic fields perpendicular to each other
the speed of light
- variable =c, constant in a vacuum
- c = 3.00 x 108 meters per second
- c = λν
divided into spectra which dictate different properties, namely whether the human eye can detect its presence and appearance in color

in the early twentieth century, matter and energy were viewed as fundamentally distinct
- matter was composed of particles
- energy was composed of waves
- this later developed into the notion that energy existed in particles
Planck then developed the theory that energy is quantized
- particles of energy are called quanta (the single form of which is quantum)
- relationship between energy and frequency: E=Hν
- energy can behave as both waves and particles
- Planck constant: constant h; 6.62 x 10^-34 joule-seconds
frequency (ν) is the bridge between the two units

properties of energy

quantized energy (detailed further in next note) is measured by Planck’s constant, units are quantum and photons
energy of photon = Planck constant x frequency

properties of matter

contain matter waves, or the wave characteristics present in material particles
momentum describes the quantity mv (mass x velocity) of any object
Heisenberg’s uncertainty principle posits that it is impossible for people to know simultaneously the exact momentum of an electron and its exact location in space
- these cannot be measured at the same time, but estimations can be made to approximate one or the other