Advertisements
Advertisements
प्रश्न
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.
उत्तर
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
संबंधित प्रश्न
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 ship on the surface of water sends a signal and receives it back from a submarine inside water after 4 s. Calculate the distance of the submarine from the ship. (The speed of sound in water is 1450 ms-1)
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.
On sending an ultrasonic wave from a ship towards the bottom of a sea, the time interval between sending the wave and receiving it back is found to be 1.5 s. If the velocity of wave in sea water is 1400 m s-1, find the depth of the sea.
A pendulum has a frequency of 4 vibrations per second. An oberver starts the pendulum and fires a gun simultaneously. He hears the echo from the cliff after 6 vibrations of the pendulum, if the velocity of sound in air is 340 m/s, find the distance betwen the cliff and the obsever.
A boy stands 66.4 m in front of a high wall and then blows a whistle. Calculate the time interval when he hears an echo. (Speed of sound = 332m/s).
A ship which is stationary at a distance of 680 m from the shore, sends a signal to the coast. Its echo is heard in 4s. Find the velocity of sound.
An observer stands at a distance of 850 m from a cliff and fires a gun. After what time gap will he hear the echo? If sound travels at a speed of 350 m/sec., in air.
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.
