Radio waves as electromagnetic waves and their applications

Steps:

• Recall that radio waves are a type of electromagnetic radiation with long wavelengths and low frequencies.
• Identify common uses: radio waves carry signals for broadcasting, including television.
• Eliminate options based on misconceptions: sound waves are mechanical, not electromagnetic.
• Compare frequencies: radio waves are below infrared, while visible light is higher.

Why C is correct:

• Radio waves are electromagnetic waves transmitted for television signals, as per the electromagnetic spectrum definition where they enable wireless communication.

Why the others are wrong:

• A: Radio waves are electromagnetic, not mechanical sound waves that require a medium.
• B: Ionizing radiation like X-rays or gamma rays, not low-energy radio waves, is used in cancer treatment.
• D: Radio waves have lower frequencies (below 300 GHz) than visible light (400–790 THz).

Final answer: C