# Sound ICSE Class 10 Physics Board Exam Questions

Students should refer to Sound ICSE Class 10 Physics Board Exam Questions provided below with solutions. These will help the students to understand the type of questions which have been asked in previous year examinations and the type of solutions which the student should give to get good marks. You should also refer to ICSE Class 10 Physics Sample papers for more practice

## ICSE Class 10 Physics Sound Important Questions

Students should learn the important questions and answers given below for Chapter Sound in Physics for ICSE Class 10. These board questions are expected to come in the upcoming exams. Students of ICSE Class 10th should go through the Important questions and answers ICSE Class 10 Physics which will help them to get more marks in exams.

### Sound ICSE Class 10 Physics Board Exam Questions

Sound ICSE Class 10 Physics Board Exam Questions

1) Will the sound be audible if the string is set into vibration on the surface of the moon? Give a reason for your answer.
Answer:
No, sound waves require a material medium for their propagation and on the moon, there is the absence of a medium. Due to this, we will not be able to hear any audible sound on the surface of the moon.

2) Why are string instruments provided with the large sound box?
Answer:
The vibrating strings on striking produce a very weak sound which cannot be heard. Therefore, these instruments are provided with a sound box. The strings set into vibration,
produce forced vibrations in the large volume of air in the sound box and thus, loud sound of the frequency of the vibrating string is produced.

3) Why is an echo not heard when the distance between the source of the sound and reflecting body is 10 m?
Answer:
The sensation of any sound persists in our ear for about 0.1 s after the sound heard dies off. If the echo is heard within this time interval the original sound and the echo cannot be distinguished. Therefore, in order to hear an echo distinctly, the minimum distance of the obstacle from the observer should be 17 m.

4) Two friends were playing on identical guitars whose strings were adjusted to give notes of the same pitch. Will the quality of the two notes be the same? Give a reason for your answer.
Answer:
Two musical instruments of the same pitch will not have same quality because the pitch depends on the frequency or wavelength whereas quality depends on the waveform.
Both the guitars emit same fundamental note but subsidiary notes will not be exactly same due to which the waveform of the two guitars will be different so they will differ in quality.

5) Bats can ascertain distances, directions, nature and size of the obstacle without eyes.
Explain how.
Answer:
Bats emit ultrasonic waves of large frequencies which are reflected from the obstacle in their path while they are flying. This gives them the idea about the distance, direction, size and nature of the obstacle.

6) When a vehicle is driven at a high speed, sometimes rattling sound is heard. Explain why.
Answer:
When a vehicle is driven at a high speed, sometimes rattling sound is produced because its body or any other part’s natural frequency matches with the natural frequency of the piston at that particular speed. Then the body of the vehicle vibrates with large amplitude and produces the rattling sound.
Tip: Piston is a disk or short cylinder fitting closely within a tube in which it moves up and down against a liquid or gas, used in an internal combustion engine of a vehicle to derive motion.

7) During lightning, first, we observe light and then hear the sound. Why?
Answer:
Lightning and thunder occur at the same time. The time difference we sense is due to the speed with which sound and light travel. The velocity of sound in air is 332 m s -1 whereas velocity of light is 3 × 10 8 m s -1 . Hence the flash of light is seen much before the thunder of lightning is heard.

8) A bucket is placed below a water-tap. We can estimate the height of the water level in the bucket from a distance simply by listening to the sound. How?
Answer:
The frequency of a note emitted by an air column is inversely proportional to its length, i.e., as the length of the air column decreases, the frequency increases, which leads to the note becoming shrill. As the water level in the bucket rises, the length of the air column of the bucket goes on decreasing and the sound emitted goes on becoming shriller.
Thus, we can estimate from a distance that bucket has been filled with water.

9) Two astronauts on the surface of the moon cannot talk to each other, why? What types of hearing aids are required by them?
Answer:
This is because the moon has no atmosphere and sound requires a material medium for its propagation. They require hearing aids capable of transmitting and detecting electromagnetic waves in order to be audible on the surface of the moon.