Which type of radiation lies between visible and microwave portions of the spectrum?

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

Answer: (B)

The main idea here is how the electromagnetic spectrum is ordered by wavelength (and frequency). Visible light sits in the middle, with ultraviolet having shorter wavelengths (higher energy) and infrared arriving after visible with longer wavelengths. Microwaves come after infrared with even longer wavelengths. So infrared lies between visible and microwave on the spectrum.

infrared wavelengths are roughly 0.75 micrometers up to about 1 millimeter. This means infrared is longer than visible light but shorter than microwaves. That’s why infrared is the correct answer. Ultraviolet and X-rays have shorter wavelengths (higher energy) than visible, and radio waves have longer wavelengths than microwaves, so they don’t fit between visible and microwave.