11Chapter SOUND 9th class

prodution of sound

• Absorption of heat
• Reflection of light
• Transmission of electricity
• Vibration of an object

Propagation of sound

• Sound travels through space without a medium
• Sound propagates through a medium by creating compressions and rarefactions in the molecules of the medium, forming a wave that carries the sound energy.
• Sound propagation is not affected by the medium
• Sound propagates by creating light waves

What are Sound waves?

• Sound waves are stationary vibrations.
• Sound waves are vibrations that travel through a medium.
• Sound waves are electromagnetic waves.
• Sound waves are particles that travel through space.

What are longitudinal waves?

• Longitudinal waves are waves that can only be observed in a vacuum.
• Longitudinal waves are waves that travel only in solids, not in liquids or gases.
• Longitudinal waves are waves in which the displacement of the medium is in the same direction as the direction of the wave propagation.
• Longitudinal waves are waves in which the displacement of the medium is perpendicular to the direction of the wave propagation.

What is Characteristics of a sound wave?

• Intensity, resonance, timbre, speed
• Frequency, amplitude, wavelength, speed
• Decibel, tone, echo, wavelength
• Velocity, pitch, loudness, frequency

Speed of sound in different media

• Speed of sound is fastest in solids, followed by gases, and slowest in liquids.
• Speed of sound is fastest in solids, followed by liquids, and slowest in gases.
• Speed of sound is fastest in liquids, followed by gases, and slowest in solids.
• Speed of sound is fastest in gases, followed by liquids, and slowest in solids.

What is Echo?

• Echo is a type of dessert.
• Echo is a reflection of sound.
• Echo is a type of music genre.
• Echo is a type of bird.

What is Reverberation ?

• Reverberation is the persistence of sound in a particular space after the original sound is produced due to multiple reflections of sound waves off surfaces within the space.
• Reverberation is the process of sound traveling in a straight line without any reflections
• Reverberation is the amplification of sound in a space
• Reverberation is the complete absence of sound in a space

Range of hearing

• 30 Hz to 25,000 Hz
• 15 Hz to 30,000 Hz
• 10 Hz to 15,000 Hz
• 20 Hz to 20,000 Hz

Applications of ultra sounds

• Cooking recipes
• Weather forecasting
• Automotive maintenance
• Medical imaging, monitoring pregnancies, guiding procedures, diagnosing conditions