Understanding Sound Travel in Air

The question asks what travels at a speed of 333 meters per second in the air, covering a distance of 333 meters in just 1 second. This speed, 333 ms^-1, is given as the speed of sound in air. To answer this, we need to understand how sound propagates through a medium like air.

How Sound Propagates: The Role of Disturbance

Sound is a form of energy that travels as waves. These waves are created by a vibrating source, which causes the particles of the medium (like air molecules) to vibrate about their equilibrium positions. This vibration is then passed on from one particle to the next. It's not the air particles themselves that travel from the source to the listener over long distances; rather, it's the disturbance, or the pattern of vibration, that moves through the medium.

Imagine a line of dominoes. When you push the first one (the source), it falls and knocks over the next one, which knocks over the next, and so on. The 'disturbance' (the falling action) travels along the line, but the individual dominoes (the particles) only move slightly from their original position before stopping or falling in place.

Similarly, in sound propagation, the energy is transferred through vibrations. The speed at which this disturbance travels through the medium is what we call the speed of sound.

Analyzing the Options

Let's look at the given options in the context of how sound travels:

• Receiver: The receiver (like our ear) is what detects the sound energy when the disturbance reaches it. The receiver itself does not travel at the speed of sound.
• Particles: The particles of the medium (air molecules) vibrate back and forth around their average positions. They do not travel continuously from the source to the receiver covering the entire distance at the speed of sound.
• Source: The source is what creates the sound (like a vibrating speaker). The source generates the disturbance, but it is not what travels through the air at the speed of sound.
• Disturbance: This refers to the pattern of vibration and energy transfer that propagates through the medium. This is exactly what travels from the source to the receiver at the speed of sound.

The speed of sound, $\text{v}$, is defined as the distance the disturbance travels per unit time. Given that the speed is $\text{v} = 333 \text{ ms}^{-1}$, in 1 second, the distance covered by the propagating disturbance is:

Distance = Speed $\times$ Time

Distance $= (333 \text{ ms}^{-1}) \times (1 \text{ s})$

Distance $= 333 \text{ m}$

Therefore, the entity that travels 333 m in 1 second at a speed of 333 ms^-1 is the disturbance.

Conclusion

Based on the understanding of sound propagation, the speed of sound refers to the speed at which the disturbance travels through the medium. Hence, in 1 second, a distance of 333 m is travelled by the disturbance.

Revision Table: Key Concepts of Sound Speed

Additional Information about Sound Waves

Sound waves in air are typically longitudinal waves. In longitudinal waves, the particles of the medium vibrate parallel to the direction in which the wave (the disturbance) is travelling. This creates areas of compression (where particles are close together) and rarefaction (where particles are spread apart) that propagate through the air.

The speed of sound in a medium depends on the properties of the medium, such as its elasticity and density. Sound generally travels faster in solids than in liquids, and faster in liquids than in gases, because the particles are closer together and can transmit the vibrations more efficiently.

• Speed of sound in air at 20°C is approximately 343 ms^-1. The value 333 ms^-1 is close to the speed of sound in dry air at 0°C.
• The speed of sound also changes with temperature. As temperature increases, the speed of sound in air increases.