Complete Question:
Remote controls use invisible light of frequency just below the visible range. This part of the electromagnetic spectrum is called A) infrared B) microwaves C) ultraviolet D) x-rays.
Correct Option:
Remote controls use invisible light of frequency just below the visible range. This part of the electromagnetic spectrum is called "infrared".
Option: A
Step-by-step explanation:
An IR remote or transmitter utilizes light to deliver signals to the system it regulates from the remote to. It produces invisible infrared light pulses which correlate to different binary codes. These codes are instructions like power-on button, volume-up and down, or channel up and down button.
The visible light color is red, with the longest wavelength and the lowest amount of energy. Infrared is the spectrum's invisible field, with wavelengths only longer than the red light. Microwaves, ultraviolet, and x-rays are all too powerful for remote control applications.