Practice Electromagnetic Spectrum in Physics

Use these practice problems to test your method after reviewing the concept explanation and worked examples.

Quick Recap

The complete continuum of all electromagnetic waves, organized in order of increasing frequency (or decreasing wavelength).

A 'rainbow' that extends far beyond visible light in both directions.

Example 1

easy
Arrange the following EM waves from lowest to highest frequency: visible light, X-rays, radio waves, ultraviolet, infrared, gamma rays, microwaves.

Example 2

medium
A photon of ultraviolet light has a wavelength of 200 \text{ nm}. What is its energy? Use c = 3 \times 10^8 \text{ m/s} and h = 6.626 \times 10^{-34} \text{ J s}.

Example 3

medium
A cell phone operates at 800 \text{ MHz} and an X-ray machine at 3 \times 10^{18} \text{ Hz}. By what factor is the X-ray frequency greater than the cell phone frequency?

Example 4

hard
The human eye detects light from 380 \text{ nm} (violet) to 700 \text{ nm} (red). What is the range of frequencies for visible light? What fraction of the full EM spectrum (from 3 \text{ Hz} radio to 3 \times 10^{20} \text{ Hz} gamma) does visible light occupy? Use c = 3 \times 10^8 \text{ m/s}.