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Flame tests

Electromagnetic radiation is all around us, it can be either natural or man made.  Some examples are sunlight, radio waves and microwaves.  Humans can only see 2% of the electromagnetic spectrum.  (For picture of this, see website below.)

Frequency (greek symbol nu) is the number of cycles that pass a given point per second.  It is measured in Hertz (Hz).  1Hz = 1 cycle/second.

Wavelength (greek symbol lambda) is the distance between successive peaks.  It is measured in meters (m). 1 nanometer (nm) = 1e-9 m, 1 Angstrom (A) = 1e-10 m.  Remember to watch the signs of the exponents!  Nanometers and Angstroms are SMALLER than meters!

Wavelength * Frequency = Speed of light (c) = 3.0e8 m/s

Therefore wavelength and frequency are inversely proportional, as one goes UP the other goes DOWN.

Energy = h * frequency.  (h is Planck's constant, h = 6.626e-34 J*s)  Energy is directly proportional to frequency, (as one goes UP, the other goes UP) and inversely proportional to wavelength, (as one goes UP, the other goes DOWN).

These are good relationships to memorize.

Here is a cool website that explains light and electromagnetic radiation, at the bottom it has a picture of the electromagnetic spectrum and a color wheel.

Something else to remember about ions - Cations are always listed first in an ionic compound, they are positively charged (+), and anions are always listed second in an ionic compound, they are negatively charged (-)!!

Posted at 10:30AM Jul 10, 2006 by CHRISTIAN, CAROLINE in General  |  Comments[0]