Question

which of the following statements about waves are true?
a. light waves are not true waves.
b. sound waves can travel through liquids.
c. waves can only move matter up and down or from side to side.
d. sound waves cannot travel through empty space.
e. light waves need matter in order to travel.

Explanation:

• Option A: Light waves are electromagnetic waves and are true waves. So, this option is false.
• Option B: Sound waves are mechanical waves. They can travel through solids, liquids, and gases. So, this option is true.
• Option C: Waves can transfer energy. In some cases (e.g., longitudinal waves like sound waves in air), matter moves in the direction of wave propagation (compression - rarefaction), not just up - down or side - to - side. So, this option is false.
• Option D: Sound waves are mechanical waves and need a medium (matter) to travel. Empty space (vacuum) has no matter for sound waves to propagate through. So, this option is true.
• Option E: Light waves are electromagnetic waves and can travel through a vacuum (do not need matter). So, this option is false.

Answer:

B. Sound waves can travel through liquids.
D. Sound waves cannot travel through empty space.