What is sound for Class 7th?

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Sound is produced by vibration. When a body vibrates, it forces the neighbouring particles of the medium to vibrate. This creates a disturbance in the medium, which travels in the form of waves. This disturbance, when reaches the ear, produces sound.

What is the speed of sound class 7?

The speed of sound is the distance travelled per unit time by a sound wave as it propagates through an elastic medium. The speed of sound is 343.2 metres per second. Q.

What is loudness of sound for Class 7?

If the amplitude of the sound wave is large, then the sound is said to be loud. The loudness of sound is directly proportional to the square of the amplitude of vibration, and it is expressed in decibel (dB). Therefore, sounds above 80 dB become noise to human ears.

What are the characteristics of sound class 7?

The five characteristics of sound are amplitude, wavelength, period, frequency, and speed or velocity.

What is unit of sound?

We measure sound intensity (also referred to as sound power or sound pressure) in units called decibels. Decibels (dB) are named in honor of Alexander Graham Bell, the inventor of both the telephone and the audiometer.

What are the types of sound?

There are many different types of sound including, audible, inaudible, unpleasant, pleasant, soft, loud, noise and music. You’re likely to find the sounds produced by a piano player soft, audible, and musical.

What is the formula of sound?

If the temperature is TC = 20 °C (T = 293 K), the speed of sound is v = 343 m/s. The equation for the speed of sound in air v = √γRTM can be simplified to give the equation for the speed of sound in air as a function of absolute temperature: v=√γRTM=√γRTM(273K273K)=√(273K)γRM√T273K≈331m/s√T273K. v=fλ.

Which is faster light or sound?

The speed of light as it travels through air and space is much faster than that of sound; it travels at 300 million meters per second or 273,400 miles per hour. Visible light can also travel through other things besides through air and through space.

What factors affect sound?

There are several important factors which affect the propagation of sound: geometric spreading, atmospheric effects, and surface effects. These are discussed separately below. This refers to the spreading of sound energy as a result of the expansion of the wavefronts.

What is the SI unit of loudness?

The loudness of sound is measured in a unit called deciBel (dB). A deciBel unit expresses the relative intensity of sounds on a scale from zero for the average least perceptible sound to about 100 dB, which is near the level most people find uncomfortably loud.

What is the unit of pitch?

The correct option is A hertz. The quantity on which the pitch of sound depends, is called frequency. Frequency is no. of oscillations made by each particle in the medium when sound propagates through it. Its S.I. unit is per second (s−1) or hertz (Hz).

What is a pitch in sound?

pitch, in music, position of a single sound in the complete range of sound. Sounds are higher or lower in pitch according to the frequency of vibration of the sound waves producing them.

How do we hear sounds?

We hear when sound waves travel through the air to our eardrum, across our middle ear, into our inner ear, and finally to the auditory centres of our brain. Our ears are always on and are continuously carrying sounds along this hearing pathway.

What type of wave is a sound wave?

Longitudinal waves A longitudinal wave is one where all the particles of the medium (such as gas, liquid or solid) vibrate in the same direction as the wave. Sound waves are longitudinal waves.

What is volume of sound?

The volume of a sound is how loud or quiet the sound is. Sounds are vibrations that travel through the air. A nail hit hard with a hammer will make a strong vibration, which means it will make a loud sound. A nail hit gently with a hammer will make a weak vibration, which means it will make a quiet sound.

What is the range of sound?

A normal human ear is able to hear sounds with frequencies from 20 Hz to 20,000 Hz. The range of 20 Hz to 20,000 Hz is called the audible frequency range. The sounds we hear comprise of various frequencies.

What is SI unit of frequency?

The SI unit for frequency is the hertz (Hz). One hertz is the same as one cycle per second.

How is sound measured?

Noise level is measured in decibels (dB). The louder the noise, the higher the decibels. Decibels can be adjusted to human hearing. Noise level is thus described in decibels A (dBA).

What is sound called?

Sound is a pressure wave which is created by a vibrating object. This vibrations set particles in the sur- rounding medium (typical air) in vibrational motion, thus transporting energy through the medium.

What are uses of sound?

  • Communication. For many animals including us, sound is a main form of communication.
  • Music.
  • Localisation.
  • Enhancing Cell Growth.
  • Being Unique.
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What are the 2 kinds of sounds?

  • Inaudible sounds are sounds that the human ear cannot detect. The human ear hears frequencies between 20 Hz and 20 KHz.
  • Sounds that are below 20 Hz frequency are called Infrasonic Sounds.
  • Sounds that are above 20 KHz frequency are called Ultrasonic Sounds.

What is the real speed of sound?

If we consider the atmosphere on a standard day at sea level static conditions, the speed of sound is about 761 mph, or 1100 feet/second.

What is the speed of sound wave?

speed of sound, speed at which sound waves propagate through different materials. In particular, for dry air at a temperature of 0 °C (32 °F), the modern value for the speed of sound is 331.29 metres (1,086.9 feet) per second.

What is a wavelength in sound?

The wavelength of a sound is the distance between adjacent identical parts of a wave—for example, between adjacent compressions as illustrated in Figure 17.8. The frequency is the same as that of the source and is the number of waves that pass a point per unit time.

Who is sound produced?

It is produced from a vibrating body. The vibrating body causes the medium (water, air, etc.) around it to vibrate thus producing sound. The sound is produced when something vibrates .

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