Question

Are frequency and wavelength constants in terms of light?

Answer 1

No. Frequency and wavelength of light change according to how much energy the light has and the medium the light is propagating in.

Explanation:

The amount of energy light has determines its frequency. Once frequency is known, the medium the light is traveling in determines its wavelength (and its velocity).

Where `E` is energy, `h` is Planck's constant and `f` is frequency:
`E=hf`

Where `\lambda` is wavelength, `v` is velocity and `f` is frequency:
`\lambda = \frac{v}{f}`

Blue light, for example, has a frequency of around `6.1\times 10^{14}` Hz and wavelength around `490`nm in a vacuum, where the velocity of light is `v = c = 2.99792458 \times10^8` m/s.

Green light in a vacuum has a frequency of `5.4\times10^{14}` Hz and wavelength of `560`nm.

There are many, many more frequencies and wavelengths of light, most of which we can't see! (Think X-rays, microwaves, gamma rays)

These values for frequency and wavelength change when the light enters a different medium, e.g. air, water, glass etc.

Scroll through this:
http://chemwiki.ucdavis.edu/Core/Physical_Chemistry/Spectroscopy/Fundamentals/Electromagnetic_Radiation