Which statement accurately contrasts electromagnetic waves with mechanical waves?

Which statement accurately contrasts electromagnetic waves with mechanical waves?

• A. Electromagnetic waves require a medium, while mechanical waves do not.
• B. Electromagnetic waves do not require a medium; mechanical waves require a medium.
• C. Both types require a medium.
• D. Electromagnetic waves travel only in a vacuum.

Answer: (B)

Electromagnetic waves can propagate through empty space because they are oscillating electric and magnetic fields that support each other and form self-sustaining waves. This means they do not need a medium to carry the energy. Mechanical waves, like sound or water waves, rely on particles in a material to vibrate and pass along energy, so they require a medium such as air, water, or a solid. That makes the statement the best choice: electromagnetic waves do not require a medium, while mechanical waves do. The other ideas aren’t correct because electromagnetic waves can travel in vacuum, not only in a medium; and not both types require a medium.

Electromagnetic waves can propagate through empty space because they are oscillating electric and magnetic fields that support each other and form self-sustaining waves. This means they do not need a medium to carry the energy. Mechanical waves, like sound or water waves, rely on particles in a material to vibrate and pass along energy, so they require a medium such as air, water, or a solid.

That makes the statement the best choice: electromagnetic waves do not require a medium, while mechanical waves do. The other ideas aren’t correct because electromagnetic waves can travel in vacuum, not only in a medium; and not both types require a medium.