Remote Controls Use IR; Satellites Use Microwaves

Steps:

• Remote controllers emit infrared waves to send signals to TVs, as IR is short-range and line-of-sight.
• Earth-to-satellite communication uses microwaves, which penetrate the atmosphere and enable long-distance transmission.
• Compare options: A pairs IR with UV (incorrect for satellites); B pairs IR with microwaves (matches both uses).
• Eliminate C and D, as visible light is not used for either application due to absorption and limited range.

Why B is correct:

• Infrared handles short-range TV remotes per standard consumer electronics; microwaves are defined for satellite links in radio frequency bands (e.g., 1-30 GHz) per ITU standards.

Why the others are wrong:

• A: Ultraviolet is ionizing and absorbed by atmosphere, unsuitable for satellite signals.
• C: Visible light scatters easily and requires direct visibility, impractical for remotes or satellites.
• D: Same as C; visible light lacks penetration for space communication.

Final answer: B