Velocity of sound is maximum in:
steel
Understanding Velocity of Sound in Different Media
The velocity, or speed, of sound depends heavily on the medium through which it travels. Sound waves are mechanical waves, meaning they require a medium (like a solid, liquid, or gas) to propagate. They travel by causing vibrations in the particles of the medium.
The speed of sound is determined by two main properties of the medium:
- Elasticity: How easily the medium returns to its original shape after being deformed. A more elastic medium allows vibrations to pass through faster.
- Density: The mass per unit volume of the medium. In general, sound travels slower in denser materials if elasticity is the same, but the elasticity effect is usually much more dominant, especially when comparing different states of matter.
Comparing Sound Speed in Different States of Matter
Sound generally travels fastest in solids, slower in liquids, and slowest in gases. This is because the particles in solids are much closer together and are strongly bonded, allowing vibrations to transfer more quickly and efficiently. Liquids have particles that are further apart and less rigidly connected than solids, while gases have particles that are very far apart and interact weakly.
Analyzing the Given Options
Let's look at the options provided:
- Hydrogen: Hydrogen is a gas. Gases typically have the lowest speed of sound compared to liquids and solids.
- Vacuum: A vacuum is the absence of a medium. Sound waves cannot travel through a vacuum because there are no particles to vibrate and transmit the sound energy. The velocity of sound in a vacuum is zero.
- Steel: Steel is a solid. Solids are generally excellent conductors of sound due to their high elasticity and relatively close-packed particles.
- Water: Water is a liquid. Sound travels faster in liquids than in gases, but typically slower than in solids.
Comparing the typical speeds of sound in these types of media:
| Medium Type | Example | Approximate Speed of Sound (m/s) |
|---|---|---|
| Gas | Hydrogen (at 0°C) | ~1284 |
| Vacuum | N/A | 0 |
| Liquid | Water (at 20°C) | ~1482 |
| Solid | Steel | ~5000 - 6000 |
As you can see from the typical values, the velocity of sound $v$ is significantly higher in steel (a solid) than in water (a liquid) or hydrogen (a gas). The velocity in a vacuum is zero.
Conclusion on Maximum Sound Velocity
Based on the properties of the media and the typical speeds of sound, steel, being a solid with high elasticity, allows sound to travel much faster than in hydrogen (a gas), water (a liquid), or a vacuum (no medium). Therefore, the velocity of sound is maximum in steel among the given options.
Revision Table: Key Factors for Sound Velocity
| Factor | Effect on Sound Velocity | Reason |
|---|---|---|
| Medium (State) | Solid > Liquid > Gas | Particles are closer and interact more strongly in solids, transmitting vibrations faster. |
| Elasticity | Higher elasticity → Higher velocity | Medium returns to original shape quickly, allowing waves to propagate faster. |
| Density | Higher density → Lower velocity (if elasticity is constant) | More mass to move, which slows down vibrations. However, elasticity usually dominates when comparing different states. |
| Temperature (for gases) | Higher temperature → Higher velocity | Particles move faster at higher temperatures, increasing vibration speed. |
Additional Information on Sound Propagation
Sound waves are longitudinal waves in fluids (gases and liquids) and can be both longitudinal and transverse in solids. The ability of solids to support shear forces (which relates to their rigidity or elasticity) is why sound often travels fastest in them. For solids, the speed of sound depends on the Young's modulus (for longitudinal waves in thin rods) or bulk modulus and shear modulus (for waves in bulk solid) and the density.
For liquids, the speed of sound depends on the bulk modulus and density.
For gases, the speed of sound depends on the adiabatic bulk modulus (which is related to the specific heat ratio $\gamma$ and pressure $P$) and density $\rho$. The formula is $v = \sqrt{\gamma P / \rho}$. Since $P/\rho$ is proportional to temperature, the speed of sound in an ideal gas is proportional to the square root of its absolute temperature and the square root of $\gamma$ and inversely proportional to the square root of its molar mass.
Important Questions from The Speed of Sound
The speed of a longitudinal wave in a solid bar is given by v = √(X/ρ), where 'ρ' is density of the medium. What is the unknown term 'X'?
At standard temperature and pressure, in which of the following media does sound propagate with the greatest speed?
The velocity of sound in air is affected by change in the
I. Moisture content of air
II. Temperature of air
III. Composition of air
IV. Atmospheric pressure
Choose the correct answer.
What is the relation between the frequency f, wavelength λ, and speed v of the sound?
An object is 10.64 km below the sea level. A research team sends down a sonar signal to confirm this depth. After how long can it expect to get the echo? Take speed of sound in sea water = 1520 m/s.
