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

• A. Visible light
• B. X-rays
• C. Ultraviolet light
• D. Radio waves

Answer: (D)

Verified step by step guidance

1. Recall the electromagnetic spectrum, which arranges types of electromagnetic radiation by their wavelength and frequency.
2. Understand that wavelength (\( \lambda \)) and frequency (\( \nu \)) are inversely related by the equation: \[ \lambda = \frac{c}{\nu} \] where \( c \) is the speed of light.
3. Identify the relative positions of the given types of radiation on the electromagnetic spectrum: X-rays have very short wavelengths, ultraviolet light has slightly longer wavelengths than X-rays, visible light has longer wavelengths than ultraviolet, and radio waves have the longest wavelengths.
4. Compare the options given (Visible light, X-rays, Ultraviolet light) with radio waves, noting that radio waves are not listed among the options but are known to have the longest wavelength in the electromagnetic spectrum.
5. Conclude that among the listed options, radio waves have the longest wavelength, which is why the correct answer is radio waves.