Olympiad Test: Sound- 2 - Class 9 MCQ

Metal plates vibrate when a musical note is produced by the cymbals in an orchestra.

Cymbal is a musical instrument that produces sound when being struck.

The sound waves given off by different vibrating bodies differ in quality, or timbre. A note from a saxophone, for instance, differs from a note of the same pitch and intensity produced by a violin or a xylophone; similarly vibrating reeds, columns of air, and strings all differ. Quality is dependent on the number and relative intensity of overtones produced by the vibrating body, and these in turn depend upon the nature of the vibrating body.

Sounds may be generally characterized by pitch, loudness, and quality. Sound quality or timbre describes those characteristics of sound which allow the ear to distinguish sounds which have the same pitch and loudness. Timbre is a general term for the distinguishable characteristics of a tone.

Hence, The quality or timbre of sound is that characteristic which enables us to distinguish one sound from one person to another having the same pitch and loudness.

Musical sound of an orchestra is not periodic at every point; rather they consist of a single frequency and it is a longitudinal wave.

Rest all waves oscillate to the path of propagation.

Cochlea converts vibrations into electrical signals. Hammer, Anvil, Stirrup are the bones of the ear. They amplify the vibrations.

Echo method is used in SONAR to determine the depth of the sea. Sound wave of 50 kHz is used to measure the depth of the sea by the echo method.

When a disturbance (energy) is produced in a medium , particles of medium start vibration about their mean position and transfer the disturbance to the next particle and come back towards their mean position .This process continues , in the forward direction to the upcoming particles of the medium at a constant rate , medium particles change their position temporarily but there is no net displacement of the medium particles. In this way a wave advances in a medium , and energy is transferred at a constant speed.

Frequency is the number of occurrences of a repeating event per unit of time.

Hence, option C is the answer.

Sound requires a medium to travel. Since there is nothing in the vacuum, sound cannot travel. As such the person with normal hearing range cannot hear it.

Sound waves travel fastest in solids .because In solids, the particles are tightly packed and the space of separation between them is less i.e the density is more. And so, the time taken for a particle to collide with another is comparatively less because they have to travel a relatively short distance with their velocity. Therefore, there are more collisions per second and particles move faster causing the wave to propagate faster, which means its speed will be high.

In a transverse wave, the motion of the medium is perpendicular to the motion of the wave. To clarify, in a water wave, the actual water molecules move up and down while the wave moves horizontally.

Longitudinal waves, in contrast, are waves in which the medium moves back and forth in the same direction as the motion of the wave. Sound waves are of this type.

For example, when we lay the slinky down on the ground and push it back and forth lengthwise it creates longitudinal waves.To make transverse waves, we shake the slinky back and forth perpendicular to the length.

Hence, a slinky can be used to produce longitudinal waves as well as transverse waves under different conditions.