SAT Subject Physics Practice Question 191: Answer and Explanation
37. Which of the following types of electromagnetic radiation has the longest wavelength?
A. Gamma rays
C. Blue light
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”).