A sound wave travels at a speed of 339 ms–1. If its wavelength is 1.5 cm, what is the frequency of the wave? Will it be audible?
Solution and Explanation
Sound Speed (v): 339 m/s
Sound Wavelength (\(λ\)): 1.5 cm = 0.015 m
The formula relating speed, wavelength, and frequency is \(v=λ×f.\)
\(f=\frac{v}{λ}=\frac{339}{0.015}\)=22600Hz
The frequency of audible sound for humans typically ranges from 20 Hz to 20,000 Hz. Given the sound frequency of 22,600 Hz, it falls outside the audible range, indicating that it is not audible to human ears.
Top Questions on Propagation of Sound
- What is loudness of sound? What factors does it depend on?
- CBSE Class IX
- Science
- Propagation of Sound
- A stone is dropped from the top of a tower 500 m high into a pond of water at the base of the tower. When is the splash heard at the top?
Given, g = 10 ms–2 and speed of sound = 340 ms–1.- CBSE Class IX
- Science
- Propagation of Sound
- The frequency of a source of sound is 100 Hz. How many times does it vibrate in a minute?
- CBSE Class IX
- Science
- Propagation of Sound
- Flash and thunder are produced simultaneously. But thunder is heard a few seconds after the flash is seen, why?
- CBSE Class IX
- Science
- Propagation of Sound
- Why is sound wave called a longitudinal wave?
- CBSE Class IX
- Science
- Propagation of Sound
Questions Asked in CBSE Class IX exam
- The text you read is a travelogue where the author, Vikram Seth, talks about his visit to two sacred places in Kathmandu. Imagine that you were with Vikram Seth on his visit to Pashupatinath temple, and you were noting down all that you saw and did there, so that you could write a travelogue later.
Record in point form • what you see when you reach the Pashupatinath temple • what you see happening inside the temple • what you do when inside the temple • what you see outside the temple • what your impressions are about the place.- CBSE Class IX
- Kathmandu
- Sergei says, “I am happy that my words have taken effect.” Why does he say so? Is he right in saying this?
- CBSE Class IX
- The beggar
- In Fig. 9.24, ∠PQR = 100°, where P, Q and R are points on a circle with centre O. Find ∠OPR.
- CBSE Class IX
- Angle Subtended by an Arc of a Circle
- How does the author describe: (i) his father, (ii) his mother, (iii) himself?
- CBSE Class IX
- My childhood
- The following table gives the distribution of students of two sections according to the marks obtained by him:
Section A
Section B
Marks
Frequency
Marks
Frequency
0 − 10
3
0 − 10
5
10 − 20
9
10 − 20
19
20 − 30
17
20 − 30
15
30 − 40
12
30 − 40
10
40 − 50
9
40 − 50
1
Represent the marks of the students of both the sections on the same graph by two frequency polygons. From the two polygons compare the performance of the two sections.- CBSE Class IX
- Graphical Representation of Data
Concepts Used:
Sound
Sound is a vibration that propagates the mechanical wave of displacement and pressure, through a medium can be of any matter. In other words, the sound is the thin line between Music sound and Noise.
Types of Sounds:
Sound can be divided into two types depending on its frequency. The following are:-
Infrasonic Waves:
- Infrasonic waves have a frequency lower than 20 Hz. Since it is below the human hearing range, it is inaudible to humans.
- However, several other living organisms use these waves to communicate, whales, sharks, elephants, hippopotamus, etc. these waves are also used in the scientific field, it is used to study upcoming earthquakes, volcanic eruptions, human heart rates, rock formation stages, etc.
Ultrasonic waves:
- Ultrasonic waves have a frequency higher than 20 kHz. Since it is above the human hearing range, it is inaudible to humans.
- These waves are used in the scientific field, it is used to study human heart rates, to take sonograms, navigation of directions, imaging things, uniform sample mixing, communication, testing of samples, etc.