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Sound Worksheet-3

Sound Worksheet-3

 

  1. A pendulum oscillates 40 times is 4 seconds. Find its time period and frequency.

 

  1. The sound from a mosquito is produced when it vibrates its wings at an average rate of 500 vibrations per seconds, what is the time period of the vibrations?

 

  1. Identify the part which vibrates to produce sound in following instruments.

(a) Dholak or tabla

(b) Sitar

(c) Flute

 

  1. What is the difference between noise and music? Can music become noise sometimes?

 

  1. List sources of noise pollution in your surroundings.

 

  1. Explain in what way noise pollution is harmful to humans?

 

  1. Which option of house is better? One on the road side and another three lanes away from the road side. Explain your answer.

 

  1. Sketch larynx and explain its function in your own words.

 

  1. Lightening and thunder take place in the sky at the same time and at the same distance from us. Lightning is seen earlier and thunder is heard later. Can you explain?

 

  1. What is sound?

 

Answer:

  1. Number of oscillations = 40

Total time = 4 seconds

Time taken to complete one oscillation = (4/40) = (1/10) = 0.1 second

So time period = 0.1 second.

Frequency = (1/Time period) = (1/0.1) = 10 Hz.

 

  1. Total vibrations = 500

Time taken = 1 second

Time taken to complete one vibration = (1/500) = 0.002 seconds.

So time period = 0.002 seconds.

 

  1. (a) Stretched membrane

(b) Strings

(c) Air column

 

  1. The sound which is unpleasant for our ears is called noise while music is the sound which is pleasant for our ears. Music becomes noise sometimes when it crosses the bearable range of sound for our ears that is more then 20000 Hz.

 

  1. Honking of horns, loud speakers, loud sounds of machines in factories, loud sounds of T.V., radio, domestic appliances etc.

 

  1. Harmful effects of noise pollution:

(i) It may cause deafness.

(ii) It may cause mental illness.

(iii) It may cause headache and high blood pressure.

(iv) It may lead to irritating behavior

 

  1. The house that is three lanes away from the roadside would safe guard our health and will give peace of mind and less noise pollution will be there.

 

  1. Larynx is also known as voice box. It has vocal cords which have air column vibrating in them, which cause sound in humans.

 

  1. The speed of light is much more than that of sound. Due to more speed the light reaches us before the sound does. So lightening is seen earlier and thunder is heard later.

 

  1. Sound is the medium by which we communicate with one another.