A sound wave has a frequency of 5 kHz and wave length 50 cm. How long (in seconds) will it take to travel 5 km?
Show answer & explanation
Correct answer: A
Explanation
Correct Answer: Option 1 (2 seconds)
Explanation:
The speed of sound is considered to be approximately 340 meters per second.
Speed is obtained by multiplying wavelength and frequency.
Here, the frequency is 5 kHz and the wavelength is 50 cm.
Speed = 5000 × 0.5 = 2500 meters per second.
Distance = 5 km = 5000 meters.
Time = Distance/Speed = 5000/2500 = 2 seconds.
Additional Facts
Frequency: It is measured in Hertz (Hz) and is the number of vibrations per second.
Wavelength: The distance between two consecutive crests or troughs is called wavelength.
Speed of Sound: The speed of sound depends on the density and temperature of the medium (fastest in solids, slowest in gases).
Possible questions for the upcoming exam
What is the average speed of sound in air at room temperature?
(Answer: Approximately 343 m/s)
What is the frequency of ultrasonic waves?
(Answer: More than 20,000 Hz)
What is the unit for measuring sound intensity?
(Answer: Decibel - dB)