Question

Question #914c6

Answer 1

1. the number of wavelengths per unit distance, `1/lambda = f/c`
2. the number of radians per unit distance.

Explanation:

1. I think you need the following :
   `1/lambda = f/c`
   Where `1/λ` is equal to the wave number,
   `f` and `c` are frequency and wave speed respectively.

It is denoted as

`\tilde{\nu} \=\ \frac{1}{\lambda}`
This definition is normally used in spectroscopy.
2. In wave equations where frequency, wavelength and wave-number are constants, it is defined as angular wave-number or simply called wave-number, represented by `k`
`k=(2pi)/lambda`