Reflection of sound

Key Concepts

1. Reflection of sound
2. Amplification
3. Reverberation
4. Echo

Explanation: 

Reflection of sound: 

The bouncing back the sound waves when it is travelled in the same medium and hits a smooth reflecting surface, the sound waves reflect the same medium is called the reflection of sound. 

Sound follows the same properties of the light reflection. 

Incident sound waves: 

The sound waves which are emitted by the source are called the incident sound wave. 

Reflected sound wave: 

The sound waves reflected in the same medium after hitting the smooth surface are called reflected sound waves. 

Sound reflection follows the same laws that of reflection of light. 

The first law of reflection: The incident wave, the reflected wave, and the normal wave of the sound should be in the same medium. 

The second law of reflection: Angle of incidence is always equal to the angle of reflection. 

 Some of the important properties of the reflection of sound.  

Reverberation: 

Reverberation is the persistence of sound. It is the reflection of sound after the sound from the source is stopped. The sound is still audible because of the reflection of sound; reverberation is the possible in the close area as the reflection of sound is necessary for the reverberation.  

Echo: 

Echo is the reflection of sound or the repetition of sound by the sound waves. The distance and the velocity the minimum distance needed to hear the echo is 25 m. The source and the reflective surface should not have an obstacle in between. 

Experiment to determine the echo distance: 

Let’s consider a man standing on the top of the hill, and there is a tall object in front of him at a distance of 10 m.  

If a man shouts his name, he will not be able to hear the echo. 

Now consider a man on the top of the hill, and a tall object is in front of him at a distance of 25 m.  

If a man shouts his name, he will be able to hear the echo, hence the minimum distance of the echo to be observed is 25 m. 

Important points in the echo: 

1. Echo is the reflection of sound  

2. The minimum distance require for the echo is 25 m 

3. Velocity of the echo is v = 2d/t 

4. As the sound travels twice the distance, hence it is taken as 2d. 

Summary:

• Reflection of sound: The sound waves bounce back when travelling in the same medium and hit a smooth reflecting surface.
• The sound waves reflected in the same medium is called the reflection of sound. Sound follows the same properties of the light reflection.
• Reverberation: Reverberation is the persistence of sound; it is the reflection of sound after the sound.
• Echo: Echo is the reflection of sound or the repetition of sound by the sound waves.