10th Science: Key Points to Remember on Acoustics

Points to Remember - Acoustics

Key Concepts in Acoustics

• Wave velocity is the velocity with which the wave travels through the medium.
• Velocity of a sound wave is maximum in solids because they are more elastic in nature than liquids and gases. Since gases are least elastic in nature.
• Infrasonic waves are sound wave with a frequency below 20 Hz. A human ear cannot hear these waves.
• Ultrasonic waves are sound waves with frequency greater than 20 kHz, A human ear cannot detect these waves.
• Reflection of sound waves obey the laws of reflection.
• when a compression hits the boundary of a rarer medium, it is reflected as a rarefaction.
• An echo is the sound reproduced due to the reflection of the original sound wave.
• The minimum distance between the source and the reflecting surface should be 17.2 m to hear an echo clearly.
• “The apparent frequency” is the frequency of the sound as heard by the listener.