Echoes may be heard more than once due to successive or multiple ________.
Reflections
The correct answer is Option 4: Reflections.
Explanation
An echo is a sound heard by a listener that is caused by the sound waves bouncing back from a hard surface (like a cliff, wall, or mountain side).
When sound waves bounce off multiple surfaces one after another, it is called successive or multiple reflections. This allows the same original sound wave to reach the listener's ears at different time intervals, causing the echo to be heard more than once. A classic real-world example of this is the rolling sound of thunder, or shouting inside a deep valley surrounded by large mountains.
Why the Other Options Are Incorrect
Option 1 (Diffractions): Diffraction is the bending of sound waves around obstacles or through narrow openings. While it allows you to hear someone talking around a corner, it does not cause distinct, repeating echoes.
Option 2 (Refractions): Refraction is the bending of sound waves when they pass from one medium into another, or through a medium with varying temperatures (which changes the speed of sound).
Option 3 (Rarefactions): A rarefaction is simply the low-pressure, spread-out segment of a longitudinal sound wave as it travels. It is a part of the wave itself, not a phenomenon that duplicates sound.
Similar Questions
An echo is returned in 3 s. What is the distance of the reflecting surface from the source, considering the speed of sound as 342 ms -1 ?
A boat at anchor is rocked by waves whose consecutive crests are 125 m apart. The velocity of the wave of the moving crests is 25 ms-1. What is the frequency of the rocking of the boat?
What is the range of frequencies of sound waves audible to human beings?
If the frequency of a sound wave of given velocity is increased, how will it affect its wavelength?
Sound travels at a speed of 333 ms -1 in the air; thus, in 1s, a distance of 333 m is travelled by ________.
A sound wave has a frequency of 4 kHz and a wavelength of 40 cm. The time taken by the sound wave to travel a distance of 3.2 km is:
To hear a distinct echo the time interval between the original sound and the reflected sound must be at least ________.
The velocity of light in vacuum is:
The repeated reflection that results in persistence of sound is called ________.
Important Questions from Wave
Which of the following is correct?
I. Sound is a mechanical wave
II. Sound wave does not need any medium to propagate
At a particular temperature, sound propagates in ______ at the fastest speed .
What is the frequency range of ultrasound?
The atmospheric green house effect is produced mainly by the absorption and re-emission of:
Which of the following are examples of electromagnetic waves?
a. Television waves
b. Ultraviolet rays
c. X-rays
d. Sun rays
