Frank solutions for फिज़िक्स पार्ट [अंग्रेजी] कक्षा १० आईसीएसई chapter 3 - Sound [Latest edition]

Give the SI unit of wavelength.

Explain how the principle of echo is used by
The bat during its flight at

Explain how the principle of echo is used by

 The dolphin to locate small fish as its prey

What is 'SONAR'?

State the principle on which SONAR is based.

Fig. shows three ways in which a string of length l in an instrument can vibrate.

(i)	(ii)	(iii)

1. Which of the diagram shows the principle note?
2. Which vibration has the frequency four times that of the first?
3. Which vibration is of the longest wavelength?
4. What is the ratio of the frequency of the vibration in (i) and (ii)?

When a troop crosses a suspension bridge, the soldiers are asked to break steps. Explain the reason.

How does the medium affect the amplitude of free/natural vibrations of a body?

Is pitch same as frequency?

What adjustments would you make for tuning a stringed instrument for it to emit a note of a desired frequency?

Explain why strings of different thicknesses are provided on a stringed instrument.

[Hint: Natural frequency of vibration of a stretched string is inversely proportional to the radius (or thickness) of string so notes of different frequencies can be produces by vibrating different strings.]

In fig. , P, Q, R and S represent test tubes each of height 20 cm which are filled with water upto heights of 10 cm, 14 cm, 16 cm and 18 cm respectively. If a vibrating tuning fork is placed over the mouth of test tube Q, a loud sound is heard.
(i) Describe the observations with the tubes P, R and S.
(ii) Give the reason for your observation in each case.
(iii) State the principle illustrated by the above experiment.

In fig. shows two tuning forks P and Q of the same frequency mounted on separate sound boxes with their open ends facing each other. The fork A is set into vibration. (i) Describe your observation. (ii) State the principle illustrated by this experiment.

In Fig. A, B, C and D are four pendulums suspended from the same elastic string XY. The lengths of pendulum A and D are equal, while the length of pendulum B is shorter and of the pendulum C is longer. Pendulum A is set into vibrations.

1. What is your observation about the vibrations of pendulum D?
2. Give reason for your observation in part (a).
3. What type of vibrations take place in pendulums Band C?
4. Give reason for the answer in part (c).

Differentiate  between the following: 
Light and sound waves.

Differentiate  between the following: 

Free and forced vibrations. 

Differentiate  between the following: 

 Radio waves and light waves.

Explain how is the principle of echo used by
(a) The bat during its flight at night,
(b) The dolphin to locate small fish as its prey.

Explain the following and illustrate your answer by drawing appropriate diagram:
Frequency

Explain the following and illustrate your answer by drawing appropriate diagram:

Loudness

Explain the following and illustrate your answer by drawing appropriate diagram:

Pitch

Explain the following and illustrate your answer by drawing appropriate diagram:

Quality of a musical note.

Define the term velocity as applied to a sound wave.

Define the relation between velocity, wavelength, and frequency of the wave.

In fig. shows a snap shot of a wave from of frequency 50 Hz in a string. The numbers in the diagram represents distance in centimeters. Fpr the wave motion, find
(a) Wavelength,
(b) Amplitude,
(c) Velocity.

Name musical instrument, one in each case, which produces its notes by using the following. In each case state the method used to produce notes of different pitches and loudness.
(a) A vibrating string.
(b) A vibrating column air.
(c) Vibration of any other body.

Give scientific reason for the following: 

Windows sometimes rattle when the low notes of a pipe organ are sounded.

Give scientific reason for the following:
When a nail is hammering appears to get higher and higher in pitch.

What determines the pitch of a sound?

How is it possible to recognize a person by his voice without seeing him?

How does the wave pattern of a loud note differ from a soft note? Draw a diagram.

Why is the loudness of the sound heard by a plucked wire increased when it is mounted on a sound board?

What change do you expect in the characteristics of a musical sound if
(i) Its frequency is increased,
(ii) Its amplitude is increased?

Comment on the statement 'loudness of sound is a subjective quantity, while intensity is an objective quantity.

In fig. 2 two musical notes of the same pitch and same loudness are played on a violin and on a piano. Their wave forms are as shown in the diagram below. Explain why the wave patterns are different.