Question

A point source emits light of only a single frequency = 6.7 x 101​ 4​ Hz. What color is the light produced?

Answer 1

Let's first find the wavelength of the light wave:

$$\lambda=\dfrac{c}{f}=\dfrac{3\cdot10^8\ \dfrac{m}{s}}{6.7\cdot10^{14}\ Hz}=448\cdot10^{-9}\ m=448\ nm.$$

Indigo color has the range of the wavelengths between 440 and 450 nanometers. Therefore, the point source produces the light of indigo color.

Answer:

$\lambda=448\ nm,$ indigo.