Advertisements
Advertisements
Question
A girl is sitting in the middle of a park of dimension 12 m × 12 m. On the left side of it, there is a building adjoining the park and on the right side of the park, there is a road adjoining the park. A sound is produced on the road by a cracker. Is it possible for the girl to hear the echo of this sound? Explain your answer.
Solution
If the time gap between the original sound and reflected sound received by the listener is around 0.1 s, only then the echo can be heard.
Speed of sound in air, v=344 ms−1
The time gap between the original sound and the reflected sound received by the girl
= `18/344"S" - 6/344 "S"`
= 0.035s
As 0.035 s < 0.1 s, therefore no echo will be heard by the girl.
APPEARS IN
RELATED QUESTIONS
What is the audible range of the average human ear?
What is the range of frequencies associated with infrasound?
What name is given to the sound waves of frequency too low for humans to hear ?
What name is given to the sound waves of frequency too high for humans to hear ?
What type of sound waves are produced by a vibrating simple pendulum ?
Which of the following sound frequencies cannot be heard by a human ear ?
(i) 10 Hz
(ii) 100 Hz
(iii) 10,000 Hz
(iv) 15 Hz
(v) 40,000 Hz
What are infrasonic waves ? Name two animals which produce infrasonic waves.
What are ultrasonic waves ? Name two animals which can produce ultrasonic waves.
The audible range of frequencies of an average human ear is from 20 Hz to 20 kHz. Calculate the corresponding wavelengths. (Speed of sound in air is 344 ms–1)
For hearing the loudest ticking sound heard by the ear, find the angle x in Fig.12.4.
