What is the approximate speed of sound in distilled water at 25°C (77°F)?

1498 m/s

The correct answer is option 1. 1498 m/s.

The speed of sound in a medium like water depends on various factors, including temperature, pressure, and the medium's properties. 

Sound waves are longitudinal mechanical waves that propagate through a medium by the successive compression and rarefaction of the medium's particles. In water, these waves travel as disturbances in the molecular structure of the liquid.

The speed of sound in a medium can be calculated using the equation:
   \[v = \sqrt{\frac{B}{\rho}}\]
   Where:
   - \(v\) is the speed of sound.
   - \(B\) is the bulk modulus of the medium, a measure of the medium's resistance to compression.
   - \(\rho\) is the density of the medium.

The bulk modulus and density of water vary with temperature. At 25°C (77°F), the bulk modulus of distilled water is approximately 2.16 × 10^9 pascals (Pa), and the density is approximately 997 kilograms per cubic meter (kg/m^3).

Substituting the values of bulk modulus and density into the speed of sound equation, we get:
   \[v = \sqrt{\frac{2.16 \times 10^9 \, \text{Pa}}{997 \, \text{kg/m}^3}} \approx 1498 \, \text{m/s}\]

The value of approximately 1498 meters per second (m/s) is commonly used as an approximation for the speed of sound in distilled water at 25°C. It may vary slightly depending on factors such as the purity of the water and any dissolved substances, but this value provides a reasonable estimate for typical conditions.

In summary, the approximate speed of sound in distilled water at 25°C (77°F) is around 1498 m/s, calculated based on the bulk modulus and density of water at that temperature.