Test: Sound - Class 10 MCQ

Damped vibrations are characterized by a decrease in amplitude over time, primarily due to resistive forces such as friction. In contrast, free vibrations maintain a constant amplitude in an ideal scenario.

Different musical instruments produce unique sounds, or timbres, because of the varying harmonic content and overtones generated when they vibrate. Each instrument's construction and materials influence these characteristics.

The unit of loudness is called the phon, which relates to the perceived loudness of sound at a specific frequency, typically 1 kHz. The decibel (dB) measures sound intensity but is not directly equivalent to loudness.

SONAR (Sound Navigation and Ranging) is primarily used to detect underwater objects by transmitting sound waves and analyzing the echoes that return after bouncing off these objects. It is essential in maritime navigation and exploration.

Music is characterized by pleasant, continuous, and uniform sounds produced by regular and periodic vibrations. This distinguishes it from noise, which consists of irregular and disruptive sounds.

Ultrasonic waves are commonly used in echocardiography to create images of the heart. This non-invasive technique helps visualize heart structure and function by reflecting sound waves off different heart tissues.

In real-world scenarios, the amplitude of a freely vibrating body decreases over time due to energy loss caused by resistive forces in the surrounding medium, such as air resistance or friction.

The human ear can typically hear sounds in the frequency range of 20 Hz to 20,000 Hz. This range defines the limits of human hearing, with sounds below 20 Hz classified as infrasonic and those above 20,000 Hz as ultrasonic.

The speed of sound in air increases with increased humidity because the presence of water vapor in the air reduces its density, allowing sound waves to travel more efficiently.

The loudness of sound is directly proportional to the square of the amplitude of the sound wave. This means that even a small increase in amplitude can lead to a significant increase in perceived loudness.

Forced vibrations occur when an external periodic force acts on a body, causing it to vibrate. The body may not vibrate at its natural frequency unless the external frequency matches it.

The speed of sound is greater on hot days than on cold days. As the temperature increases, the molecules in the medium move faster, allowing sound waves to travel more quickly.

Noise pollution, characterized by loud and undesirable sounds, can lead to permanent hearing damage, especially at levels above 120 dB. Continuous exposure to such noise can cause significant health issues.

The distinct quality or timbre of a sound is influenced by the presence of harmonic frequencies, or overtones, that combine to create the unique sound characteristics of each instrument, even when they play the same note.

Free vibrations occur in the absence of external forces and maintain constant amplitude. They are characterized by the natural frequency of the vibrating body and can occur in a vacuum.

A longitudinal wave is produced when the vibrations of medium particles occur in the same direction as the wave propagation. This wave type is characterized by compressions and rarefactions within the medium.

When the frequency of an external periodic force aligns with the natural frequency of the vibrating body, resonance occurs. This results in increased amplitude of vibrations and can lead to dramatic effects, such as a bridge vibrating due to foot traffic.

The pitch of a sound is directly related to its frequency; as the frequency of vibration increases, the pitch becomes higher. This is why instruments tuned to higher frequencies produce sharper, more acute sounds.

A distinct echo can be heard if the distance to the obstacle is at least 17 m, allowing sufficient time for the sound to bounce back and be perceived separately from the original sound.

A tuning fork demonstrates resonance when another tuning fork of the same frequency is placed nearby. The vibrations from the first fork can cause the second to vibrate with increased amplitude due to the matching frequencies, illustrating the principle of resonance effectively.