Class 9 Science Sound Extra Question Answer
If you are looking for Class 9 Science Sound Extra Question Answer then your search ends here…………….
Q: What is sound?
A: Sound is a form of energy which produces a sensation of hearing in our ears and is produced by vibrating objects.
Q: How does sound travel through a medium?
A: Sound travels through a medium as longitudinal waves, creating a series of compressions and rarefactions.
Q: What is a compression in sound waves?
A: A compression is a region of high pressure and density where particles of the medium are crowded together.
Q: What is wavelength in sound waves?
A: Wavelength is the distance between two consecutive compressions or two consecutive rarefactions in a sound wave.
Q: What determines the loudness of sound?
A: The amplitude (height) of the sound wave determines its loudness – larger amplitude means louder sound.
Q: What determines the pitch of sound?
A: The frequency of sound waves determines pitch – higher frequency means higher pitch.
Q: What is the audible range of sound for humans?
A: The audible range for humans is 20 Hz to 20,000 Hz.
Q: What is an echo?
A: An echo is the reflection of sound that reaches the listener at least 0.1 seconds after the original sound.
Q: What is reverberation?
A: Reverberation is the persistence of sound due to repeated reflections from surfaces in an enclosed space.
Q: At what temperature is the speed of sound in air 331 m/s?
A: The speed of sound in air is 331 m/s at 0°C.
Q: What is infrasound?
A: Infrasound refers to sound waves with frequencies below 20 Hz.
Q: What is ultrasound?
A: Ultrasound refers to sound waves with frequencies above 20,000 Hz.
Q: Which travels faster – sound in water or sound in steel?
A: Sound travels faster in steel than in water.
Q: What is a stethoscope based on?
A: A stethoscope works on the principle of multiple reflection of sound.
Q: Why are concert hall ceilings often curved?
A: Ceilings are curved so that sound after reflection reaches all corners of the hall uniformly.
Q: What is the relationship between speed, frequency and wavelength of sound?
A: Speed = Wavelength × Frequency (v = λν)
Q: What type of wave is a sound wave?
A: Sound waves are mechanical longitudinal waves.
Q: Name one application of ultrasound in medicine.
A: Ultrasonography – using ultrasound waves to image internal organs of the body.
Q: What is the minimum distance needed for an echo to be heard?
A: Approximately 17.2 meters at 22°C.
