Electromagnetic radiation

Electromagnetic radiation (EMR) is a form of energy that is all around us and takes many forms, such as radio waves, microwaves, X-rays and gamma rays. Sunlight is also a form of EM energy, but visible light is only a small portion of the EM spectrum, which contains a broad range of electromagnetic wavelengths.

Overview

Electromagnetic radiation is a type of energy that is commonly known as light. Generally speaking, we say that light travels in waves, and all electromagnetic radiation travels at the same speed which is about 3.0 * 10^8 meters per second through a vacuum. We call this the speed of light. Nothing can go faster than the speed of light.

Types of Electromagnetic Radiation

The different types of electromagnetic radiation shown in the electromagnetic spectrum are produced by different processes. These are:

• Radio Waves: Produced by the acceleration of an electron in a radio antenna.
• Microwaves: Produced by special vacuum tubes (klystrons, magnetrons and Gunn diodes).
• Infrared: Produced by the vibration and rotation of atoms and molecules (also by an incandescent object).
• Visible Light: Produced by transitions of outer shell electrons in atoms excited by heat or light.
• Ultraviolet: Produced by transitions of inner shell electrons in atoms excited by heat or light.
• X-Rays: Produced by high energy processes such as bombarding a metal target in a vacuum with high-speed electrons.
• Gamma Rays: Produced by nuclear processes such as radioactive decay and nuclear reactions.

Health Effects

Exposure to certain forms of electromagnetic radiation can be harmful. The higher the frequency of the radiation, the more damage it is likely to cause to the body: microwaves can burn skin, X-rays can damage cells and gamma radiation can cause radiation sickness.

See Also

• Electromagnetic Spectrum
• Radio Waves
• Microwaves
• Infrared
• Visible Light
• Ultraviolet
• X-Rays
• Gamma Rays

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