Newton's calculation of the speed of sound in air was approximately 281 meters per second. This was a significant historical attempt to derive the speed of sound theoretically using the isothermal assumption, which was later corrected by Laplace to account for adiabatic processes, leading to the more accurate value of approximately 331-340 m/s.

Sound propagation depends on the elasticity and density of the medium. Solids have much higher elastic moduli than liquids or gases, meaning the particles are more tightly coupled. This allows the mechanical vibrations of sound to transfer energy more rapidly between atoms, resulting in the highest speed of sound in solids.

The audible frequency range refers to the spectrum of sound vibrations that the human auditory system can detect, typically spanning from 20 Hz to 20,000 Hz. Frequencies outside this range are classified as infrasonic or ultrasonic.

The speed of sound depends on the elasticity and density of the medium. Solids are generally much more elastic than liquids or gases, allowing sound waves to propagate faster through them. Sound cannot travel through a vacuum at all, as it requires particles to transmit mechanical vibrations.

The speed of sound in dry air at 0°C is experimentally determined to be approximately 331 meters per second. The correct SI unit for velocity is meters per second, denoted as m/s or m·s⁻¹. Option B correctly identifies both the numerical value and the standard scientific notation for the unit.

An echo is a distinct sound caused by the reflection of sound waves from a surface back to the listener. For an echo to be perceived, the reflected sound must reach the ear at a sufficient time delay after the original sound, typically requiring a minimum distance from the reflecting surface.

Sound is a mechanical longitudinal wave that travels through a medium such as air. As the source vibrates, it creates periodic compressions and rarefactions in the medium, resulting in fluctuations in local air pressure that propagate outward as a wave.

The relationship between wave speed (v), frequency (f), and wavelength (λ) is given by the formula v = fλ. Given v = 330 m/s and λ = 10 cm = 0.1 m, we calculate f = v / λ = 330 / 0.1 = 3300 Hz, which is equivalent to 3.3×10^3 Hz.

The speed of sound in a gas depends on its density and temperature. Moist air (containing water vapor) is less dense than dry air at the same temperature and pressure. Since sound travels faster in less dense media, it propagates more efficiently through humid air, allowing it to be heard over greater distances.

The total distance traveled by the sound is 340 m/s * 0.3 s = 102 meters. Since the sound travels to the wall and back, the distance to the wall is half of the total distance: 102 / 2 = 51 meters.