Test: Propagation Of Sound Waves - Class 9 MCQ

The speed of sound in water at 0°C is approximately 1450 m/s, which is significantly faster than in air due to the higher density and elasticity of water compared to gases.

Sound cannot travel through a vacuum because there are no particles to transmit the mechanical vibrations necessary for sound propagation. Thus, sound intensity cannot be measured in a vacuum.

Ultrasonic sound refers to frequencies above 20 kHz, which are inaudible to humans but can be detected by some animals and are used in various technological applications.

Frequency and wavelength are inversely proportional; as the frequency of a wave increases, its wavelength decreases. This relationship is expressed mathematically as wave velocity being the product of frequency and wavelength.

Humans can typically hear sounds in the frequency range of 20 Hz to 20 kHz. This range can vary based on age and individual sensitivity, with younger people often able to hear higher frequencies.

The speed of sound increases when the wind blows in the same direction as the sound. Conversely, it decreases if the wind is blowing against the sound's direction.

Sound is primarily produced by vibrating objects, which create mechanical waves that travel through a medium. When these vibrations disturb the surrounding particles, they generate sound waves that we can hear.

Humans are most sensitive to frequencies between 2000 Hz and 3000 Hz, where we can detect even faint sounds, illustrating how frequency impacts our auditory perception.

Light travels much faster than sound. The speed of light in air is approximately 3 × 10^8 m/s, while sound travels at about 343 m/s in air, which is why we see lightning first before hearing the thunder.

Sound travels mainly as longitudinal waves, where the particles of the medium vibrate in the same direction as the wave travels, creating areas of compression and rarefaction.

Sound travels fastest in solids, and among the options listed, steel transmits sound at approximately 5100 m/s, significantly faster than in liquids or gases.

Bats utilize ultrasonic waves for echolocation, allowing them to navigate and hunt in the dark by emitting high-frequency sounds and listening for their echoes.

Infrasonic sound refers to frequencies that are lower than 20 Hz. These sounds are inaudible to humans but can be perceived by some animals, such as elephants.

Sound requires a material medium (solid, liquid, or gas) to travel. It cannot propagate through a vacuum, as there are no particles to transmit the vibrations that create sound.

The speed of sound in a gas is independent of pressure. As pressure increases, density also increases proportionally, keeping the P/ρ ratio constant, which means speed remains unchanged.

Ultrasound's high frequency and directivity allow it to produce clear images in medical imaging techniques, such as ultrasonography, by reflecting off tissues and organs.

At room temperature, the speed of sound in air is approximately 343 m/s. However, the commonly cited value at 0°C is around 330 m/s, so this may vary slightly based on conditions.

The speed of sound in gases increases with temperature. As temperature rises, the density of the gas decreases, allowing sound waves to travel faster. For every 1°C increase in air temperature, the speed of sound increases by about 0.61 m/s.

Amplitude is defined as the maximum displacement of a particle in the medium from its rest position. It represents the energy of the wave; greater amplitude means louder sound.

Wavelength is the distance between two consecutive compressions or rarefactions in a longitudinal wave or between two consecutive crests in a transverse wave.