Test: Sound - Class 8 MCQ

A larger vibrating surface area allows more energy to be transmitted into the surrounding medium, resulting in louder sounds. For example, beating a large drum produces a louder sound than a smaller drum struck with the same force.

Pitch is determined by the frequency of the sound waves; higher frequencies correspond to higher pitches, while lower frequencies relate to lower pitches.

The frequency is calculated as the reciprocal of the time period. Thus, frequency = 1 / 0.5 seconds = 2 Hz. This indicates the wave completes 2 cycles per second.

Amplitude is the term used to describe the maximum displacement of particles from their rest position in a wave. It is crucial in determining the loudness of the sound produced, with higher amplitudes resulting in louder sounds.

Sound is classified as a form of energy that is produced when an object vibrates, causing waves that travel through different mediums. This energy enables us to hear various sounds, such as music and voices.

The loudness of sound is directly proportional to the amplitude of the wave. A larger amplitude means more energy is transmitted, resulting in a louder sound.

The threshold of hearing is measured at 0 dB, indicating the faintest sound that the average human ear can detect. Sounds above this level can be perceived, with increasing intensity measured in decibels.

A region of compression is created when particles of the medium move closer together due to the forward motion of a vibrating object. This area is vital for the propagation of sound waves through the medium.

Rarefaction refers to regions in a sound wave where particles are farther apart than their normal positions. This is contrasted with compression, where particles are closer together. Both are essential for the propagation of longitudinal waves.

Frequency is measured in hertz (Hz), which indicates the number of vibrations or cycles per second. This measurement is essential for understanding the pitch of a sound.

The quality or timbre of a sound allows us to distinguish between different sources, even if they produce sounds of the same pitch and loudness. This is due to the unique waveforms produced by different instruments or voices.

The relationship is defined as frequency being the reciprocal of the time period, meaning frequency (f) equals 1 divided by the time period (T). This relationship indicates how many vibrations occur in one second.

The speed of sound increases in warmer conditions. This is because higher temperatures give particles more kinetic energy, allowing them to vibrate and transmit sound waves more rapidly.

Loudness is measured in decibels (dB). This scale quantifies sound intensity, with 0 dB representing the threshold of hearing and higher values indicating louder sounds.

Shortening the length of the vibrating air column in wind instruments increases the pitch. This is because a shorter column allows for higher frequency vibrations, leading to a higher pitch.

The timbre or quality of sound is primarily influenced by the waveform. Different instruments create unique waveforms, which allows us to distinguish sounds that may have the same pitch and loudness.

Sound intensity decreases as the distance from the source increases. This is because the energy of the sound wave spreads out over a larger area, making it less perceptible as one moves further away.

Thicker strings produce a lower pitch due to their mass and tension characteristics. When strings are plucked, their thickness influences the frequency of vibration, thus altering the pitch.

A monotone sound is characterized by having only one frequency. An example of this is a tuning fork, which produces a pure tone when struck.

Sound travels fastest through solids because the particles are more closely packed, allowing vibrations to transfer more quickly compared to liquids and gases. For instance, sound travels at about 5000 m/s in iron, significantly faster than in water or air.