What is the most important source of electromagnetic radiation on earth?
the oceans
the moon
volcanos
the sun
The most important source of electromagnetic radiation on Earth is the sun. Electromagnetic waves travel from the sun to Earth across space and provide virtually all the energy that supports life on our planet. Many other sources of electromagnetic waves that people use depend on technology. Radio waves, microwaves, and X rays are examples. We use these electromagnetic waves for communications, cooking, medicine, and many other purposes. You’ll learn about all these types of electromagnetic waves in this chapter’s lesson on "The Electromagnetic Spectrum. ".