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Transmit sound is a Vacuum.

Time Period given by the inverse of the frequency.

Time period = \(\frac{1}{frequency}\)

1. Pitch refers to the sharpness or shrillness of sound.

2. Increase in frequency of sound results in increase in the pitch and the sound is said to be sharper.

3. Tone refers to a single frequency of a wave.

4. A note may contain single or multiple tones.

5. High frequency is generally referred as high pitch or high tone.

6. Generally, speech of the men is of low pitch (shrill) and that of the women is of high pitch (sharp). Tones of an acoustic guitar are sharper than that of a base guitar. Sound of table is sharper than that of a dagga.

The Physical quantity is Frequency

The unit of frequency is called “hertz”.

The SI unit of frequency is hertz (Hz). The number of vibrations (complete waves or cycles) produced in one second is called frequency of the wave.

Correct option is  B) Air < liquid < solid

With increase in humidity, density of air decreases. So with rise in humidity velocity of sound increases. This is why sound travels in humid air (rainy season or winter) than in dry air (summer) at the same temperature.

Supersonic speed

In case of thunder, we see the lightening first and then the sound of thunder. This is because, the velocity of light in air is while the velocity of sound in air is 343 m/s.

Supersonic speed means the speed of an object which greater than the speed of sound.

A stone is dropped on the surface of water in a pond name transverse waves .

One observation from everyday life which shows that sound travels much more slow than light is during monsoons. We first see the lightning and then hear the sound of thunder.

The two types of waves are longitudinal waves and transverse waves.

If sound waves are generated in air, the state of compression and rarefaction created in the air moves away from the source. [Note: The air does not move away from the source because air is elastic and the force due to the tuning fork varies periodically with time.]

Yes, vibrating ruler pushes the molecules in the air producing sound waves. More the length of free part of ruler less will be the vibrations and less will be the frequency and pitch of the sound. If the length of free part of ruler is shorter it vibrates more quickly producing sound of higher frequency and pitch.

1. No, If the ruler kept on the table is only a little part off the table, it will not vibrate with a greater force. 

2. On the contrary if the ruler is kept with a larger portion off the table it will vibrate with a greater force generating louder sound.

i. When the girl makes 60 claps in 1 minute, the value of speed of is 340 m/s. 

ii. The girl is at a distance of 226.67 m from the wall when she produces 45 claps per minute.

[Note: The answer given above is calculated in accordance with textual method considering the given data]

The phenomenon responsible for producing a loud audible sound is named resonance. The vibrating tuning fork causes the forced vibrations in the air column. For a certain length of air column, a loud sound is heard. This happens when the frequency of the air column becomes equal to the frequency of the tuning fork.

Correct Answer is: (d) 8/7

Let n_o and n_c be the fundamental frequencies of the open and closed pipes.

∴ n_o = V/2l and n_c =V/4l_c .

Third overtone of the closed pipe = 7n_c. 

Third overtone of the open pipe = 4n_o.

The disturbance produced in the environment by undesirable and loud sound from the various sources is called noise pollution. Loudspeaker, noise produced by heavy duty vehicles or railways trains, etc.

C. vibrating strings 

The vibrating strings modes is utilized in the production of sound by humans.

1. Humans cannot hear frequency less than 20 Hz. In the movement of hands oscillations does take place but is less than frequency that humans can hear.

2. Mosquitos wings flap in air.

3. When they fly in air it produces buzzing sound in our ears.

4. The movement of mosquito wings produces sound greater than 20 Hz.

5. Sound is the reception of such waves and their perception by the brain.

X : Ultrasonic sound waves (Greater than 20,000Hz) 

Y : Infrasonic sound waves (0-20 Hz) 

Z : Audible sounds (20Hz-20,000Hz)

There will be more noise in the house which is along the roadside due to noise produced by transportation vehicles may cause trouble to the residents. On the other hand, the house which is three lanes away from the roadside would be quieter. Therefore, it is better to take the house that is three lanes away from the roadside.

The pitch of the sound we hear depends on the frequency of the sound wave. A high frequency sound wave has a high pitch, and a low frequency sound has a low pitch.

When sound travels from one medium to another, both its velocity and the wavelength changes. When the sound travels from air to water the speed of the sound increases.

Membrane of the drum vibrates to produce the sound. When the membrane is struck it generates a movement of air the shell amplifies the sound of the drum head developing into a sound wave.

There will be more noise in the house which is along the roadside due to the noise produced by transportation vehicles. But, the house which is three lanes away from the roadside would have comparatively less noise. Therefore, it is better to take the house that is three lanes away from the roadside.

(a) The time period = 1/f = 1/500 = 0.002 secs. 

(b) The frequency of the vibrations in hertz is 500 Hz. Because 1Hz = 1 vibration/second. 

(c) We can hear this because it is in the range of 20Hz to 20,000Hz.

Eardrum vibrates when outside sound falls on it.

(a) Hammer, Anvil, Stirrup are the three ear bones. 

(b) Strirup is in touch with oval window. 

(c) Hammer is in touch with the ear drum. 

(d) Anvil is in touch with the other two bones.

The three bones help in transmitting the sound into the middle ear.

The auditory nerve carries electrical impulses from the cochlea of ear to the brain

Correct option is C) vibration

Objects to be cleansed are put in a cleaning solution and ultrasonic sound waves are passed through that solution. The high frequency of these ultrasound waves detaches the dirt from the objects.

Objects to be cleaned are placed in a cleaning solution and ultrasonic waves are sent into the solution. Due to high frequency, the particles of dust, grease and dirt get detached and drop out. The objects thus get thoroughly cleaned.

Speed = Distance travelled / time taken

Speed = 1020 /3 = 340 m/s

B) 20 cycles /sec – 20,000 cycles/sec