# Question 914c6

Mar 20, 2016
1. the number of wavelengths per unit distance, $\frac{1}{\lambda} = \frac{f}{c}$
2. the number of radians per unit distance.

#### Explanation:

1. I think you need the following :
$\frac{1}{\lambda} = \frac{f}{c}$
Where 1/λ # is equal to the wave number,
$f$ and $c$ are frequency and wave speed respectively.

It is denoted as

$\setminus t i l \mathrm{de} \left\{\setminus \nu\right\} \setminus = \setminus \setminus \frac{1}{\setminus \lambda}$
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 $k$
$k = \frac{2 \pi}{\lambda}$