electromagnetic spectrum

a spectrum of electromagnetic waves

Visible light and infrared light are just a small part of the full range of electromagnetic radiation, which is called the electromagnetic spectrum. You can see the waves of the electromagnetic spectrum in the Figure 1.1. At the top of the diagram, the wavelengths of the waves are given. Also included are objects that are about the same size as the corresponding wavelengths. The frequencies and energy levels of the waves are shown at the bottom of the diagram. Some sources of the waves are also given. On the left side of the electromagnetic spectrum diagram are radio waves and microwaves. Radio waves have the longest wavelengths and lowest frequencies of all electromagnetic waves. They also have the least amount of energy. On the right side of the diagram are X rays and gamma rays. They have the shortest wavelengths and highest frequencies of all electromagnetic waves. They also have the most energy. Between these two extremes are waves that are commonly called light. Light includes infrared light, visible light, and ultraviolet light. The wavelengths, frequencies, and energy levels of light fall in between those of radio waves on the left and X rays and gamma rays on the right. Q: Which type of light has the longest wavelengths? A: Infrared light has the longest wavelengths. Q: What sources of infrared light are shown in the diagram? A: The sources in the diagram are people and light bulbs, but all living things and most other objects give off infrared light.

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electromagnetic radiation

Electromagnetic radiation is energy that travels in waves across space as well as through matter. Most of the electromagnetic radiation on Earth comes from the sun. Like other waves, electromagnetic waves are characterized by certain wavelengths and wave frequencies. Wavelength is the distance between two corresponding points on adjacent waves. Wave frequency is the number of waves that pass a fixed point in a given amount of time. Electromagnetic waves with shorter wavelengths have higher frequencies and more energy.

instructional diagrams

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questions

most of the electromagnetic radiation on earth comes from the sun.

-->  a. true

b. false

electromagnetic waves with longer wavelengths have

a) higher frequencies.

b) more energy.

c) faster speeds.

-->  d) none of the above

electromagnetic waves with the longest wavelengths are

a) gamma rays.

b) x rays.

c) infrared light.

-->  d) radio waves.

electromagnetic waves with the greatest amount of energy are

a) microwaves.

b) ultraviolet light.

c) infrared light.

-->  d) gamma rays.

the frequencies of electromagnetic waves range from

-->  a) 104 to 1020 waves/second.

b) 108 to 1016 waves/second.

c) 1010 to 1014 waves/second.

d) none of the above

the only electromagnetic waves in sunlight are ultraviolet, infrared, and visible light.

a. true

-->  b. false

ultraviolet light has more energy than visible light.

-->  a. true

b. false

diagram questions

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