Goyal Brothers Prakashan solutions for A New Approach to ICSE Physics Part 1 [English] Class 9 chapter 9 - Sound [Latest edition]

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In case of longitudinal waves, the particles of the medium vibrate:

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A longitudinal wave consists of:

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The longitudinal waves can propagate only in

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A part of the longitudinal wave in which particles of the medium are closer than the normal particles is called:

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A part of longitudinal wave in which particles of the medium are farther away than the normal particles is called :

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In the region of compression or rarefaction, in a longitudinal wave, the physical quantity which does not change is:

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The wavelength is the linear distance between the:

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The number of oscillations passing through a point in unit time is called:

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The SI unit of frequency is

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If the frequency of a wave is 25 Hz. the total number of compressions and rarefactions passing through a point in 1 second is :

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Which of the following is an elastic wave?

What do you understand by the term sound energy?

State three conditions necessary for hearing sound.

Describe briefly an experiment to prove that vibrating bodies produce sound.

What do you understand by the term infrasonic vibrations?

What do you understand by the term sonic vibrations? State the range of sonic vibrations for the human ear.

What do you understand by the term ultrasonic vibrations?

Name three animals which can hear ultrasonic vibrations.

How do bats locate their prey during a flight?

What is Galton’s whistle? To what use is it put?

State four practical uses of ultrasonic vibrations.

Describe an experiment to prove that a material medium is necessary for the propagation of sound.

Why do astronauts talk to each other through radio telephone in space?

Define the term wavelength.

Define the term amplitude.

Define the term frequency.

State four differences between the sound wave and the light wave.

What is meant by the term wave motion?

State the relation between the wavelength and the frequency.

What kinds of waves are produced in solids, liquids, and gases?

The sound of an explosion on the surface of a lake is heard by a boat man 100 m away and by a diver 100 m below the point of explosion.

(i) Who would hear the sound first: boatman or diver?

(ii) Give a reason for your answer in part (i).

(iii) If sound takes time t to reach the boatman, how much time approximately does it take to reach the diver? 

What is approximate value of the speed of sound in iron as compared to that in air? Illustrate your answer with a simple experiment.

A continuous disturbance is created on the surface of water in a ripple tank with a small piece of cork floating on it. Describe the motion of the cork. What does the motion of the cork tell about the disturbance?

Draw a displacement-time graph for water wave.

200 waves pass through a point in one second. Calculate the time period of wave.

A bat emits an ultrasonic sound of frequency 0.25 MHz. Calculate the time in which one vibration is completed.

The sonic boom of an aircraft has a time period of 0.00005s. Calculate the frequency of sound produced.

An electromagnetic wave has a time period of 4 × 10^-8 s. Calculate its frequency in MHz.

Ultraviolet radiation has a wavelength of 300Å. If the velocity of the electromagnetic wave is 3 × 10⁸ ms^-1. Calculate:

1. frequency
2. time period.

The wavelength of the vibrations produced on the surface of water is 2 cm. If the wave velocity is 16 ms^-1, calculate:

1. no. of waves produced in one second
2. time required to produce one wave.

A continuous progressive transverse wave of frequency 8 Hz moves across the surface of a ripple tank

With reference to the frequency, describe the movement of water on the surface

A continuous progressive transverse wave of frequency 8 Hz moves across the surface of a ripple tank

If the wavelength of the transverse wave is 32 mm, calculate the speed with which wave travels across the surface of the water.

A thin metal plate is placed against the teeth of cog wheel. Cog wheel is rotated at a speed of 120 rotations per minute and has 160 teeth. Calculate:

1. frequency of node produced.
2. speed of sound, if wavelength is 1.05 m.
3. what will be the effect when the speed of cog wheel is doubled?

A sound wave of wavelength 1/3 m has a frequency 996 Hz. Keeping the medium same, if frequency changes to 1328 Hz. Calculate

1. velcoity of sound
2. new wavelength.

Two tuning forks A and B of frequencies 256 Hz and 192 Hz respectively are vibrated in air. If the wavelength of A is 1.25 m, calculate the wavelength produced by B.

The distance between one crest and one trough of a sea wave is 4.5 m. If the waves are produced at the rate of 240/min, calculate the time period.

The distance between one crest and one trough of a sea wave is 4.5 m. If the waves are produced at the rate of 240/min, calculate the wave velocity.

The distance between three consecutive crests of wave is 60 cm. If the waves are produced at the rate of 180/ min, calculate:

1. wavelength
2. time period
3. wave velocity.

The diagram given below shows a displacement distance graph of a wave. If the velocity of wave is 160 ms-1, calculate:

1. wavelength
2. frequency
3. amplitude.

From diagram given below calculate:

1. velocity of P and Q
2. frequency of P, when frequency of Q is 512 Hz.

Assume that both wave are traveling in same medium.