Mrs. Sheridan Chemistry

Equations

Density

D = m/V

V = m/D

m = V•D

Speed

distance/time

e.g. m/s or mi/hr


Speed of light
c = 2.998 • 108 m/s

Planck's constant
h = 6.626 • 10-34 J•s

Wavelength of light (lambda)
λ is in meters

Frequency of light (nu)
ν is in reciprocal seconds, 1/s, or Hz (same thing)

Speed of light(c)=wavelength(λ)•frequency(ν)

Energy of a photon of light = h • frequency (ν)

Example
A photon of light has a frequency of 5.45 • 1014 Hz.
What is its wavelength and energy? 
It is in the visible range. What color light is it?

nu(ν)=5.45•1014Hz=5.45•1014 1/s
c=3.00•108 m/s


Use:
(3.00•108m/s)/(5.45•1014
1/s)

= 5.50 • 107 m

Then, 5.50 • 107 m = 550 nanometers, which is slightly
greenish-yellow

To find its energy, use Planck's equation:

=(6.626•10-34J•s)•(5.45•1014 1/s)
 
= 3.61 • 10-19 Joules

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