Question

What is the wavelength of an infrared wave with a frequency of 4.2E14 Hz?

Answer 1

We will have the following:

First, we recall that:

`\lambda=(v)/(f)`

Then, we recall that the speed of light is 299 792 458 m/s; then:

`\begin{gathered} \lambda=(299792458m/s)/(4.2\ast10^(14)Hz)\Rightarrow\lambda=7.137915667\ast10^(-7)m \\ \\ \Rightarrow\lambda\approx7.1\ast10^(-7)m \end{gathered}`

So, the wavelength is approximately 7.1E-7 m.