Question

What is an example of an electromagnetic radiation practice problem?

Answer 1

Background: Electromagnetic radiation moves at the speed of light in a vacuum. The speed of light, `c`, to three significant figures, is `3.00xx10^8"m/s"`. The relationship between wavelength, `lambda`, and frequency, `f`, is `c=lambda*f`.

Question: If the wavelength of a photon of red light is `725"nm"`, what is its frequency?

Answer:
Convert `725"nm"` to meters. (`1"m"=1xx10^9"nm"`)
`725 cancel"nm"xx(1 "m")/(1xx10^9 cancel"nm")=7.25xx10^(-7) "m"`

Rearrange `c=lambda*f` to solve for `f`.

`f=c/lambda = (3.00xx10^8 cancel("m")/s")/(7.25xx10^(-7) cancel(m)`= `4.14xx10^14 "/s"=4.14xx10^14 "Hz"`