Which statement correctly describes a key difference between a radio wave and a sound wave?

• A. A radio wave requires a material medium to propagate, whereas a sound wave can travel through vacuum.
• B. Radio waves are longitudinal waves in air, whereas sound waves are transverse waves in vacuum.
• C. A radio wave is an electromagnetic wave that can travel through vacuum, whereas a sound wave is a mechanical pressure wave that requires a material medium.
• D. Both radio waves and sound waves are electromagnetic waves, but radio waves have higher frequencies.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the nature of radio waves. Radio waves are a type of electromagnetic wave, which means they consist of oscillating electric and magnetic fields and do not require a material medium to propagate. They can travel through the vacuum of space.
2. Step 2: Understand the nature of sound waves. Sound waves are mechanical waves that propagate through the vibration of particles in a medium such as air, water, or solids. They are longitudinal waves, meaning the particle displacement is parallel to the direction of wave propagation.
3. Step 3: Compare the propagation requirements. Since sound waves rely on particle vibrations, they cannot travel through a vacuum where there are no particles. In contrast, radio waves, being electromagnetic, can travel through vacuum without any medium.
4. Step 4: Clarify wave types and mediums. Radio waves are transverse electromagnetic waves, while sound waves are longitudinal mechanical waves. This difference is fundamental to their propagation characteristics.
5. Step 5: Summarize the key difference. The correct statement highlights that radio waves can travel through vacuum as electromagnetic waves, whereas sound waves require a material medium to propagate as mechanical pressure waves.