Advertisements
Advertisements
Question
The wavelength and frequency of the sound wave in a certain medium is 40 cm and 835 Hz respectively. In the same medium if another wave has a wavelength equal to 32 cm, calculate its frequency.
Solution
Given: λ = 40 cm = 0.40 m, f = 835 Hz
V = f × λ = 825 × 0.40 = 334 ms−1
In the second case, since the medium is same so the velocity of sound will remain the same.
Now V = 334 ms−1, λ = 32 cm = 0.32 m
From V = fλ
∴ f = `"V"/"λ"=334/0.32` = 1043.75 Hz.
APPEARS IN
RELATED QUESTIONS
The wavelength of waves produces on the surface of water is 20 cm. If the wave velocity is 24 m s-1, calculate:
- the number of waves produced in one second, and
- the time in which one wave is produced.
What should be the minimum distance between source and reflector in water so that echo is heard distinctly?
(The speed of sound in water = 1400 m s-1)
A man standing 25 m away from a wall produces a sound and receives the reflected sound.
- Calculate the time after which he receives the reflected sound if the speed of the sound in air is 350 m/s-1.
- Will the man be able to hear a distinct echo? Explain the answer.
A RADAR sends a signal with a speed of 3 x 108 m s-1 to an aeroplane at a distance of 300 km from it. After how much time is the signal received back after reflection from the aeroplane?
A pendulum has a frequency of 5 vibrations per second. An observer starts the pendulum and fires a gun simultaneously. He hears echo from the cliff after 8 vibrations of the pendulum. If the velocity of sound in air is 340 ms-1, find the distance between the cliff and the observer.
A person standing between the two vertical cliffs produces a sound. Two successive echoes are heard at 4 s and 6 s. Calculate the distance between the cliffs.
(Speed of sound in air = 320 ms-1)
A boy standing in front of a wall at a distance 17 m produces 10 claps per second. He notices that the sound of his clapping coincides with the echo. Echo is heard only once when clapping is stopped. Calculate the speed of sound.
An observer standing in front of a vertical wall claps 10 times one second. He adjusts his distance from the wall in such a way that the second of his clapping coincides with the echo. This happens when bis distance from the wall is 17.5m. What is the velocity of sound heard by him?
An instrument is able to detect the reflected waves from an enemy aeroplane, after a time interval of 0.02 milliseconds. If the velocity of the waves is 3 × 108 ms−1, calculate the distance of the plane from the radar.
