A sound wave has a frequency of 1 kHz and wavelength 50 cm. How long will it take to travel 1 km?

To find the time taken for the sound wave to travel 1 km, we first calculate the wave speed using the relationship between frequency (f) and wavelength (λ). The formula for wave speed (v) is v = f × λ. Given a frequency of 1 kHz (1000 Hz) and a wavelength of 50 cm (0.5 m), the speed is calculated as 1000 Hz × 0.5 m = 500 m/s [1]. Once the speed is determined, the time (t) required to travel a specific distance (d) is found using the formula t = d / v. For a distance of 1 km (1000 m), the time taken is 1000 m / 500 m/s = 2 seconds. This calculation follows standard SI unit conversions where distance is in meters and frequency in Hertz to ensure the speed is in meters per second.

Sources

1. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 8: Measurement of Time and Motion > Speed = Total distance covered Total time taken > p. 113