Chapter 10 Sound Question Answers

Important Terms to Learn Before Starting Making Notes 🗒

Amplitude (अम्लान): The maximum extent of a vibration or oscillation, measured from the position of equilibrium.

Eardrum (कान का ड्रम): A thin membrane that vibrates in response to sound waves and transmits them to the middle ear.

Frequency (आवृत्ति): The number of cycles of a periodic wave occurring per unit of time, typically measured in hertz (Hz).

Hertz (Hz) (हर्ट्ज़): The unit of frequency, equal to one cycle per second.

Larynx (कंठ): The part of the respiratory tract containing the vocal cords, also known as the voice box.

Loudness (ऊंचाई): The subjective perception of the intensity of sound, often correlated with amplitude.

Noise (शोर): Unwanted or unpleasant sound that disrupts the auditory environment.

Oscillation (अवरोधन): The repetitive variation, typically in time, of some measure about a central value or between two or more different states.

Pitch (तार): The perceived frequency of sound waves, determining how high or low a tone sounds.

Time Period (कालक्रम): The duration of one cycle of a repeating event or phenomenon, such as the time taken for one complete vibration or oscillation.

Vibration (कंपन): The rapid back and forth movement of an object around a central point.

Voice Box (कंठ): Another term for the larynx, containing the vocal cords.

Wind Pipe (वायु नलिका): The trachea, a tube-like structure that connects the larynx to the lungs, allowing air to pass to and from the lungs for breathing.

Exercise Question Starts Here: Start Working 🖊️

1. Choose the correct answer.

Sound can travel through

(a) gases only

(b) solids only

(d) solids, liquids, and gases (ठोस, तरल और गैस)

2. Voice of which of the following is likely to have minimum frequency?

(a) Baby girl

(b) Baby boy

(d) A woman

3. Tick ‘T’ for True and ‘F’ for False.

(a) Sound cannot travel in vacuum. (T) (ध्वनि निर्वात में यात्रा नहीं कर सकती)

(b) The number of oscillations per second of a vibrating object is called its time period. (F) (कंपन करने वाली वस्तु के प्रति सेकंड होने वाले दोलनों की संख्या को उसका समय अवधि कहा जाता है)

(d) For human ears, the audible range is 20 Hz to 20,000 Hz. (T) (मानव कानों के लिए श्रव्य सीमा 20 हर्ट्ज से 20,000 हर्ट्ज है)

(e) The lower the frequency of vibration, the higher is the pitch. (F) (कंपन की आवृत्ति जितनी कम होगी, पिच उतनी ही ऊँची होगी)

(f) Unwanted or unpleasant sound is termed as music. (F) (अनचाही या अप्रिय ध्वनि को संगीत कहा जाता है)

(g) Noise pollution may cause partial hearing impairment. (T) (शोर प्रदूषण से आंशिक श्रवण क्षति हो सकती है)

4. Fill in the blanks with suitable words.

(a) Time taken by an object to complete one oscillation is called time period (समय अवधि).

(b) Loudness is determined by the amplitude (आयाम) of vibration.

(d) Unwanted sound is called noise (शोर).

(e) Shrillness of a sound is determined by the frequency (आवृत्ति) of vibration.

5. A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.

Time Period (समय अवधि) = Total time / Number of oscillations = 4 seconds / 40 = 0.1 seconds
Frequency (आवृत्ति) = Number of oscillations / Total time = 40 / 4 seconds = 10 Hz

6. The sound from a mosquito is produced when it vibrates its wings at an average rate of 500 vibrations per second. What is the time period of the vibration?

Time Period (समय अवधि) = 1 / Frequency = 1 / 500 = 0.002 seconds

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

(a) Dholak (ढोलक): Membrane (झिल्ली)

(b) Sitar (सितार): Strings (तार)

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

Noise (शोर): Unwanted or unpleasant sound.

Music (संगीत): Pleasant and organized sound.

Yes, music can become noise if it is too loud or disturbing.

9. List sources of noise pollution in your surroundings.

Traffic on the road
Loudspeakers
Construction sites
Factories
Airplanes

10. Explain in what way noise pollution is harmful to human.

Hearing loss
Stress and anxiety
Sleep disturbances
Difficulty in concentrating
High blood pressure

11. Your parents are going to buy a house. They have been offered one on the roadside and another three lanes away from the roadside. Which house would you suggest your parents should buy? Explain your answer.

I would suggest buying the house three lanes away from the roadside because it will be quieter and have less noise pollution, making it a more peaceful place to live.

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

The larynx, or voice box (स्वर यंत्र), is located in the throat. It produces sound when air passes through it, causing the vocal cords to vibrate.

13. Lightning 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 why?

Lightning is seen earlier than thunder because light travels faster than sound. Light from the lightning reaches our eyes almost instantly, while sound from the thunder takes more time to reach our ears.

Chapter 10 Sound Question Answers

Important Terms to Learn Before Starting Making Notes 🗒

Exercise Question Starts Here: Start Working 🖊️

1. Choose the correct answer.

2. Voice of which of the following is likely to have minimum frequency?

3. Tick ‘T’ for True and ‘F’ for False.

4. Fill in the blanks with suitable words.

5. A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.

6. The sound from a mosquito is produced when it vibrates its wings at an average rate of 500 vibrations per second. What is the time period of the vibration?

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

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

9. List sources of noise pollution in your surroundings.

10. Explain in what way noise pollution is harmful to human.

11. Your parents are going to buy a house. They have been offered one on the roadside and another three lanes away from the roadside. Which house would you suggest your parents should buy? Explain your answer.

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

13. Lightning 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 why?

Other Chapter Question Answers: 👉

Like this:

Important Terms to Learn Before Starting Making Notes 🗒

Exercise Question Starts Here: Start Working 🖊️

1. Choose the correct answer.

2. Voice of which of the following is likely to have minimum frequency?

3. Tick ‘T’ for True and ‘F’ for False.

4. Fill in the blanks with suitable words.

5. A pendulum oscillates 40 times in 4 seconds. Find its time period and frequency.

6. The sound from a mosquito is produced when it vibrates its wings at an average rate of 500 vibrations per second. What is the time period of the vibration?

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

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

9. List sources of noise pollution in your surroundings.

10. Explain in what way noise pollution is harmful to human.

11. Your parents are going to buy a house. They have been offered one on the roadside and another three lanes away from the roadside. Which house would you suggest your parents should buy? Explain your answer.

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

13. Lightning 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 why?

Other Chapter Question Answers: 👉

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