How Sound Travels - Free MCQ Practice Test with solutions, Class 7 Year

Ultrasound refers to sound waves with frequencies higher than the human hearing range (above 20 kHz). High-frequency sounds have a higher pitch, and ultrasound is used in applications like medical imaging and animal communication.

Frequency is measured in Hertz (Hz), which represents the number of vibrations or cycles per second in a sound wave. For example, a sound with a frequency of 440 Hz corresponds to the musical note A4.

Sound is produced when an object vibrates, sending waves of energy through a medium.

Amplitude refers to the magnitude of vibrations in a sound wave, directly influencing how loud or soft the sound is perceived.

A guitarist can make their guitar sound louder by plucking or strumming it harder to increase the amplitude of vibration of the string. In an orchestra, the stringed instruments are played using a bow. The players can bow harder to increase the amplitude and therefore make a louder sound.

Sound requires particles to transmit vibrations. In a vacuum (space devoid of particles), sound waves cannot travel.

Decreasing the length of a guitar string by pressing it against a fret increases the frequency of its vibration. Shorter strings vibrate faster, producing a higher frequency and thus a higher-pitched sound.

Sound intensity decreases as the distance from the sound source increases due to spreading of the sound waves over a larger area.

The cochlea contains tiny hair cells that convert mechanical vibrations into electrical signals that are then sent to the brain.

Pitch of sound is determined by its frequency, which is the number of vibrations per second. Higher frequency sounds have higher pitch.