CBSE Class 8 Science Chapter 10 Sound LAQs

CBSE Class 8 Science Chapter 10 Sound Long Answer Questions

Question 1. Anjali’s grandfather was talking to her about the quality of sound produced by different musical instruments. The instruments like sitar, harmonium, flute, etc., give us a pleasant sensation of hearing. The dholak on the other side creates a noise.

1. Mention the name of the vibrating part of the sitar.
Answer: The String of the sitar is a vibrating part of the sitar.

Read And Learn More CBSE Class 8 Science Long Answer Questions

” Sitar vibrating part explanation “

2. Briefly explain how the loudness is created by the dholak.
Answer: If we beat the dholak, then the membrane of the dholak starts vibrating with high amplitude, and as a fact, the loudness is directly proportional to the square of the amplitude. Therefore, in the form of the loudness is created by beating the dholak.

3. We hear a shrilling sound from the flute. Explain why?
Answer: The sound wave produced by the flute is regularly curving, so there is no part of the noise. Thus, we hear the shrilling sound of the flute.

” Cbse Class 8 Science Chapter 10 Activities “

” Sound Activities For Class 8 Cbse “

4. Mention the values displayed by Anjali’s grandfather.
Answer: The values displayed by Anjali’s grandfather are scientific methods and critical thinking.

Question 2. A pendulum oscillates 40 times in 4s. Find its time and frequency.
Answer:

Given, number of oscillations =40
Time token =4 s

As we know, the number of oscillations per second is the frequency.

⇒ \(\text { Frequency }=\frac{\text { Number of oscillations }}{\text { Time taken }}\)

⇒ \(=\frac{40}{4}=10 \mathrm{~Hz}\)

Time period \(=\frac{1}{\text { Frequency }}\)

⇒ \(=\frac{1}{10}=0.1 \mathrm{~s}\)

” CBSE Class 8 Science Chapter 10 LAQs “

Question 3. Sketch, explain its functions in your own words
words.
Answer: In humans, the sound is produced by the voice box, also called the larynx. We can easily feel this part of the body by putting our lingers on the throat and find a hard hump tluit seems to move when we swallow.

” Sound long answer questions Class 8 “

1. Structure
2. It is the upper end of the windpipe.
3. Two vocal cords are stretched across the voice box or larynx.
4. The vocal cords are stretched in such a manner that it leaves a narrow slit between them for the passage of air.
5. Working
6. When the lungs force air through the slit, the vocal cords vibrate and hence, produce sound.
7. Muscles attached to the vocal cords can make the cords tight or loose.
8. When the vocal cords are tight and thin, the type or quality of voice is different from that when they are loose.

” Pitch and frequency relationship Class 8 “

Question 4. Aditi hangs four steel dishes of the same size but different thickness. She hits each of them with an iron rod.

” Vibrating parts of musical instruments Class 8 “

Based on the above picture, answer the following questions. The thicker the dish, the lower the vibration will be. Which dish will produce the loudest sound when hit?

1. Dish 2
2. Dish 4
3. Dish 1
4. Dish 3

Answer: 3. Dish 1

Which of these statements proves that sound can travel through solids?

1. We can hear the sound of the wind.
2. We can hear the sound of lightning.
3. We can hear a bell ringing from a distance.
4. We can hear heartbeats by using a stethoscope.

Answer: 2. We can hear the sound of lightning.

” Loudness and amplitude in sound Class 8 “

Which part of the human ear vibrates on receiving sound waves?

1. Ear Lobe
2. Eardrum
3. Inner Ear
4. Ear Canal

Answer: 3. Inner Ear

Question 5. Raghav kept a mini sound player in each of the two similar containers. He then tightly covered both containers with stretched plastic sheets. He placed some tiny rubber beads on the surface of the sheets. The picture shows what Raghav noticed when he turned ON the sound player.

” Frequency and time period of a pendulum “

1. Which of these questions can be answered using the result of Raghav’s activity?

1. Does sound travel as waves?
2. Does it sound product vibration?
3. Does sound travel through a vacuum?
4. Does sound travel faster in solids than in gases?

Would the result of Raghav’s activity change if fewer beads had been used? Explain your answer.

2. The picture shows four sound waves

” Human larynx anatomy and function “

Based on the above picture, answer the following questions

1. Which sound wave has the highest pitch?
Answer: 1-b 2. The number of beads will not change the result activity because the vibration of the plastic sheet depends on the sound.

2. Which of these is true about the four sound waves?
Answer: High frequency produces high pitch. Hence, wave 2 has the highest pitch.

(a) Yes (b) Yes (c) No

” Sound waves and their properties Class 8 “