Question

What is the wavelength of violet light with a frequency of `750*10^12` `Hz`?

Answer 1

I found `400nm`

Explanation:

You can use the relationship between frequency, `nu`, wavelength, `lambda` and speed of light (in vacuum), `c`, given as:
`c=lambda*nu`
rearranging:
`lambda=c/nu=(3xx10^8)/(750xx10^12)=0.004xx10^(8-12)=0.004xx10^(-4)=4xx10^(-7)m=400nm`