Acoustics and Sound Waves

Sound waves are longitudinal waves because the particle displacement is parallel to the direction of wave propagation. Transverse waves involve displacement perpendicular to the direction of travel.

Hertz is the SI unit of frequency, defined as one cycle per second. Speed, amplitude, and wavelength are physical properties that are measured in different units like m/s, meters, or decibels.

Hertz is the SI unit of frequency, defined as one cycle per second. Speed, amplitude, and wavelength have different units like meters per second, meters, or decibels.

Sound waves are longitudinal waves, meaning the displacement of the medium is parallel to the direction of wave propagation. Light, microwave, and ocean waves are transverse.

Sound is a mechanical wave that requires a medium to propagate. Since a vacuum contains no particles to transmit the vibrations, sound cannot travel through it.

Ultrasound is defined by its frequency, which is above the range of human hearing (typically above 20,000 Hz). Audible sound falls within the 20 Hz to 20,000 Hz range.

Sound waves require a medium to travel. The speed of sound depends on the medium's elasticity and density; solids have much higher elastic moduli than liquids, which allows sound waves to propagate faster.

Sound waves exhibit reflection, refraction, interference, and diffraction. Polarization is a property unique to transverse waves, such as light, whereas sound waves are longitudinal and cannot be polarized.

Thunder is caused by the rapid expansion of air due to lightning. The sound reflects off various surfaces like clouds, mountains, and buildings, creating multiple echoes that result in the characteristic rumbling sound.

The human ear can detect sound intensities starting from 0 dB (the threshold of hearing) up to about 180 dB (which causes immediate damage). The other ranges listed are far beyond the threshold of pain.

Sound travels fastest in solids because the particles are more closely packed together, allowing for more efficient transmission of mechanical vibrations. Steel is a dense solid.

The decibel (dB) is a logarithmic unit used to measure the intensity or level of sound.

The outer ear is called the ‘pinna’. It collects the sound from the surroundings.

Hence, option 1 is correct.

Resonance occurs when an external periodic force is applied to a system at its natural frequency, causing it to vibrate with large amplitude. This is a specific case of forced vibrations.

Sound waves are mechanical waves that transport energy through a medium. They do not transport mass (particles only oscillate) and do not transport 'sound' itself - sound is the energy wave. The wave carries energy from source to receiver.