Which of the following electromagnetic waves has the longest wavelength?
Correct answer: D. Radio waves
- A. Gamma rays
- B. X rays
- C. Visible light
- D. Radio waves
Explanation
The spectrum runs from radio waves at the long wavelength, low frequency, low energy end through microwaves, infrared, visible light and ultraviolet to X rays and gamma rays at the other extreme. Since all travel at the same speed, the longest wavelength necessarily has the lowest frequency. Photon energy is proportional to frequency, which is why gamma rays are the most damaging.
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About Electromagnetic Waves
Electromagnetic waves consist of mutually perpendicular, oscillating electric and magnetic fields that also remain perpendicular to the direction of propagation. They travel through vacuum at the speed of light and include radio waves, microwaves, infrared, visible, ultraviolet, X-rays and gamma rays. Unlike mechanical waves, they do not require a material medium.
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