Question

1. which statement correctly distinguishes between mechanical and electromagnetic waves?

electromagnetic waves carry energy through particles that move up and down; mechanical waves carry energy through particles that move side to side.
electromagnetic waves carry energy through matter; mechanical waves carry energy through space.
mechanical waves carry energy through matter; electromagnetic waves carry energy through space.
mechanical waves carry energy through particles that move up and down; electromagnetic waves carry energy through particles that move side to side.

Explanation:

To solve this, we recall the properties of mechanical and electromagnetic waves:

• Mechanical waves (e.g., sound, water waves) require a medium (matter) to travel. They transfer energy through the vibration of particles in the medium.
• Electromagnetic waves (e.g., light, radio waves) do not require a medium and can travel through empty space (vacuum) by oscillating electric and magnetic fields.

Now, analyze the options:

• First option: Incorrect. The direction of particle motion (up/down vs. side/side) is not the key distinction between mechanical and electromagnetic waves. Also, electromagnetic waves do not rely on particle motion (they travel through space without a medium).
• Second option: Incorrect. It reverses the medium requirement: Electromagnetic waves do not need matter, and mechanical waves do.
• Third option: Correct. Mechanical waves need matter (medium) to carry energy, while electromagnetic waves carry energy through space (no medium needed).
• Fourth option: Incorrect. Similar to the first option, the direction of particle motion is not the defining difference, and electromagnetic waves do not use particle motion.

Answer:

C. Mechanical waves carry energy through matter; electromagnetic waves carry energy through space. (Assuming the third option is labeled C; adjust the label based on the original question’s numbering, but the text of the correct option is "Mechanical waves carry energy through matter; electromagnetic waves carry energy through space.")