Which statement best describes what makes sounds travel faster?

Which statement best describes what makes sounds travel faster?

• A. Larger sound sources and longer wavelengths
• B. Lower temperatures and lighter materials
• C. Denser materials or higher temperatures
• D. In vacuum and outer space

Answer: (C)

Sound speed depends on how readily a medium transmits a pressure disturbance, which is governed by its stiffness (elastic modulus) and density. The basic relationship shows that the wave travels faster when the material is effectively stiffer relative to its density, so a denser material that is also very stiff can carry sound more quickly. Temperature also plays a role: as temperature rises, particle motion increases, and in gases this makes pressure disturbances propagate faster, increasing the speed of sound. In short, higher temperature, especially in gases, and materials that are stiff enough (often associated with higher density) tend to make sound travel faster. The other ideas don’t fit because the speed of sound isn’t set by the size of the sound source or the wavelength, and sound cannot propagate at all in a vacuum.

Sound speed depends on how readily a medium transmits a pressure disturbance, which is governed by its stiffness (elastic modulus) and density. The basic relationship shows that the wave travels faster when the material is effectively stiffer relative to its density, so a denser material that is also very stiff can carry sound more quickly. Temperature also plays a role: as temperature rises, particle motion increases, and in gases this makes pressure disturbances propagate faster, increasing the speed of sound. In short, higher temperature, especially in gases, and materials that are stiff enough (often associated with higher density) tend to make sound travel faster.

The other ideas don’t fit because the speed of sound isn’t set by the size of the sound source or the wavelength, and sound cannot propagate at all in a vacuum.