Advertisements
Advertisements
प्रश्न
A person standing between two vertical cliffs and is 640 m away from the nearest cliff. He shouted and heard the first echo after 45s and the second echo after further 3s. Calculate the speed of sound in air and the distance between the cliffs.
उत्तर
Given: d1 = 640m; t1 = 4s
t2 = 4 + 3 = 7
First echo is heard from the nearest cliff.
Total distance travelled = 2d = 2 × 640 = 1280 m
v = `(2"d"_1)/"t"_1=1280/4` = 320 m/s
Second echo is heard from the first cliff
v = `(2"d"_2)/"t"_2`
⇒ 320 ms−1 = `("2d"_2)/7`
d2 = `(320xx7)/2` = 1120 m
hence, the distance between two cliff
d1 + d2 = 640 + 1120 = 1760 m.
APPEARS IN
संबंधित प्रश्न
A radar sends a signal to an aircraft at a distance of 30 km away and receives it back after 2 x 10-4 seconds. What is the speed of the signal?
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 man standing 48 m away from a wall fires a gun. Calculate the time after which an echo is heard. (The speed of sound in air is 320 ms-1).
A man fires a gun and hears its echo after 5 s. The man then moves 310 m towards the hill and fires his gun again. This time he hears the echo after 3 s. calculate the speed of sound.
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.
What is the range of audibility?
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 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.
