Question

What is the color of a wave that has a frequency of 600.0 terahertz?

Answer 1

Green

Explanation:

A terahertz is `10^12` hertz, it is a unit of frequency.

600 THz = `600 times 10^12` Hz

Let's convert this to nanometers and the look this up in a table to see what color our eyes would see. A nanometer is `10^-9` m.

Converting to nanometers is not strictly necessary, but as an optical astronomer, I have a better intuition for the color of things given in the wavelength of their light.

`v = f lambda`
`lambda = v /f`

Where `lambda` is the wavelength, and `v` is the velocity of our wave. Since we are dealing with light, we know the velocity is `c = 3 times 10^8 m/s`.

`lambda = {3 times 10^8 m/s} / {600 times 10^12 Hz}`

`lambda = 5 times 10^-7 m`
`lambda = 500 nm`

Using the table here
we see that this is green light.