If a wave shows rhythmic oscillation in distance, what is it?

If a wave shows rhythmic oscillation in distance, what is it?

• A. A sound wave
• B. Not a sound wave
• C. A radio wave
• D. An electromagnetic wave

Answer: (A)

Rhythmic oscillation in distance points to a mechanical wave where particles in a medium move back and forth as the wave passes. In a sound wave, air (or another medium) experiences compressions and rarefactions, so neighboring particles periodically move closer together and then farther apart. That back-and-forth displacement along the direction of travel is the hallmark of a sound wave. Electromagnetic waves, including radio waves, are oscillations of electric and magnetic fields and can propagate through vacuum without moving matter, so they don’t involve the regular particle-to-particle distance changes described here.

Rhythmic oscillation in distance points to a mechanical wave where particles in a medium move back and forth as the wave passes. In a sound wave, air (or another medium) experiences compressions and rarefactions, so neighboring particles periodically move closer together and then farther apart. That back-and-forth displacement along the direction of travel is the hallmark of a sound wave. Electromagnetic waves, including radio waves, are oscillations of electric and magnetic fields and can propagate through vacuum without moving matter, so they don’t involve the regular particle-to-particle distance changes described here.