Which type of electromagnetic wave has the longest wavelength?

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

Answer: (C)

Verified step by step guidance

1. Recall the electromagnetic spectrum, which arranges electromagnetic waves 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 types of waves listed: Ultraviolet waves, Gamma rays, Radio waves, and X-rays, and know their relative positions on the electromagnetic spectrum.
4. Recognize that Gamma rays have the shortest wavelengths and highest frequencies, followed by X-rays, then Ultraviolet waves, and Radio waves have the longest wavelengths and lowest frequencies.
5. Conclude that among the options given, Radio waves have the longest wavelength because they are located at the low-frequency, long-wavelength end of the electromagnetic spectrum.