Physics Sound Waves Quiz

Sound Waves

• Sound waves travel through various mediums like air, water, wood, and biological tissue.
• Sound waves require a medium for transmission; they cannot travel in a vacuum.
• Sound waves are longitudinal waves, meaning their vibrations are parallel to the direction of energy propagation.
• Sound waves are composed of compression and rarefaction patterns.
• Compression occurs when molecules are densely packed together.
• Rarefaction occurs when molecules are spaced apart.

Types of Waves

• Longitudinal waves: Particle movement is parallel to the wave's direction of travel.

  • Example: Sound waves in air or fluids. The particles in the medium vibrate back and forth in the same direction the wave is traveling

• Transverse waves: Particle movement is perpendicular to the wave's direction of travel.

  • Example: Waves on a string or water waves

Speed of Sound

• The speed of sound depends on the medium.
• Denser mediums typically transmit sound faster.
• A sound wave traveling 700 meters in 2 seconds has a speed of 350 m/s.
• The speed of sound in dry air at 20°C is approximately 343 m/s.

Sound Intensity

• Sound intensity is the power per unit area carried by a sound wave
• Measuring sound intensity uses a logarithmic scale called decibels (dB).
• More intense sound corresponds to a larger amplitude of oscillations.
• Louder sounds usually have larger amplitudes, while quiet sounds have less amplitude.

Pitch

• Pitch is a subjective measure of how high or low a sound is perceived to be.
• Pitch relates to the frequency of the sound wave
• Higher-frequency sound waves are perceived as higher-pitched
• Lower-frequency sound waves are perceived as lower-pitched

Quality/Timbre

• Timbre distinguishes sounds that have the same pitch and loudness.
• The quality of a sound depends on the shape of the sound wave's waveform.
• Different waveforms for instruments playing the same note give the characteristic sounds of instruments

Interference

• When two or more waves overlap, they combine to produce an interference pattern.
• Constructive interference increases amplitude when waves are in phase.
• Destructive interference deceases amplitude when waves are out of phase.

Reflection

• When a sound wave hits a surface, some of the wave bounces off, called reflection.

Refraction

• When a sound wave passes into another material, the speed and direction of the wave can change due to refraction.
• The change of speed is dependent on the properties of the mediums involved.

Diffraction

• Diffraction occurs when sound waves spread out as they pass through an opening or around obstacles.
• The amount of diffraction depends on the wavelength of the sound wave and the size of the opening or obstacle. 

Spherical Waves

• Spherical waves are waves that spread out from a point source, like a loudspeaker.
• Spherical waves exhibit symmetry and strength which diminishes with increasing distance from the source.
•  They can also be coherent when the waves maintain a consistent phase relationship, producing interference patterns.

Applications of Spherical Waves

• Used to model sound fields, light propagation, and detection of objects using sonar and radar techniques.