PREVIOUSLY ASKED IN:
WBPSC Miscellaneous Preliminary 2023
Answer
0 m/s
Explanation
Sound is a mechanical, longitudinal wave that requires a material medium (solid, liquid, or gas) to propagate. In a vacuum, there are no particles to vibrate and transmit the sound energy. Therefore, sound cannot travel through a vacuum, making its speed exactly 0 m/s.
Key Points
- > Sound cannot travel without a physical medium.
- > The speed of sound in air at STP is approx 332 m/s.
- > Sound travels fastest in solids (like steel) and slowest in gases.
- > Light (electromagnetic wave) can travel through a vacuum.
- > The speed of light in a vacuum is \\( 3 \\times 10^8 \\) m/s.
- > Astronauts use radios in space because sound waves can't propagate there.
- > Sound waves are longitudinal, meaning particles vibrate parallel to the wave direction.
Additional Information
Wave Speeds in Different Media
| Medium | Speed of Sound | Speed of Light |
|---|---|---|
| Vacuum | 0 m/s | \\( 3 \\times 10^8 \\) m/s |
| Air (STP) | 332 m/s | \\( \\approx 3 \\times 10^8 \\) m/s |
| Water | 1480 m/s | \\( 2.25 \\times 10^8 \\) m/s |
| Steel/Iron | 5960 m/s | Opaque to light |
Memory Tips
- Remember that Sound needs Stuff (matter). No stuff (vacuum) = No sound (0 m/s). Light doesn't need stuff.