SAT Subject Physics Practice Question 191: Answer and Explanation

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Question: 191

37. Which of the following types of electromagnetic radiation has the longest wavelength?

A. Gamma rays
B. Ultraviolet
C. Blue light
D. X-rays
E. Orange light

Correct Answer: E


Gamma rays and X-rays are very high-energy, short-wavelength radiations. Ultraviolet light has a higher energy and shorter wavelength than visible light. Within the visible spectrum, the colors are—in order of increasing frequency—ROYGBV, so orange light (“O”) has a lower frequency—and thus a longer wavelength—than blue light (“B”).

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