With reference to the production of sound, consider the following statements: 1. Sound is a form of energy that produces a sensation of hearing. 2. It is possible to produce sound without the utilization of any energy. 3. Vibration refers to the unidirectional motion of an object. Which of the statements given above is/are correct?

Correct Option The correct option is (a) 1 only. Explanation Sound is a mechanical wave that propagates through a medium. It is fundamentally a form of energy generated by the vibration of objects, which creates pressure variations in the surrounding medium. Statement-wise Analysis - Statement 1 is Correct: Sound is a form of energy that produces the sensation of hearing. It is generated when an object vibrates and transmits energy through a medium (solid, liquid, or gas) to the receiver's ear. - Statement 2 is Incorrect: The production of sound strictly requires the utilization of energy. According to the law of conservation of energy, energy is transformed from one form to another. For instance, mechanical energy used to strike a drum or pluck a guitar string is converted into sound energy. It is impossible to produce sound without an input of energy. - Statement 3 is Incorrect: Vibration is defined as the rapid to-and-fro or back-and-forth motion of an object about a central equilibrium position. It is an oscillatory motion, not a unidirectional (one-way) motion. Key Takeaway: Sound is a form of energy produced by the oscillatory (to-and-fro) motion of particles, known as vibration, and always requires an external energy source for its generation.

NCERT Class 9 Science — Chapter 5: Sound

mcqeasy

With reference to the production of sound, consider the following statements:

Sound is a form of energy that produces a sensation of hearing.
It is possible to produce sound without the utilization of any energy.
Vibration refers to the unidirectional motion of an object.

Which of the statements given above is/are correct?

Official previous-year question

Verified 1 Aug 2026.

Options

A1 only
B2 only
C1 and 3 only
D1, 2 and 3

Did you get this right?

Solution

Correct Option

The correct option is (a) 1 only.

Explanation

Sound is a mechanical wave that propagates through a medium. It is fundamentally a form of energy generated by the vibration of objects, which creates pressure variations in the surrounding medium.

Statement-wise Analysis

Statement 1 is Correct: Sound is a form of energy that produces the sensation of hearing. It is generated when an object vibrates and transmits energy through a medium (solid, liquid, or gas) to the receiver's ear.
Statement 2 is Incorrect: The production of sound strictly requires the utilization of energy. According to the law of conservation of energy, energy is transformed from one form to another. For instance, mechanical energy used to strike a drum or pluck a guitar string is converted into sound energy. It is impossible to produce sound without an input of energy.
Statement 3 is Incorrect: Vibration is defined as the rapid to-and-fro or back-and-forth motion of an object about a central equilibrium position. It is an oscillatory motion, not a unidirectional (one-way) motion.

Key Takeaway: Sound is a form of energy produced by the oscillatory (to-and-fro) motion of particles, known as vibration, and always requires an external energy source for its generation.

Your note

More from Chapter 5: Sound

Consider the following statements regarding the propagation of sound: 1. The disturbance created by a source travels through the medium to the listener. 2. Sound waves are characterized as non-mechanical waves. 3. A material medium is mandatory for the transmission of sound. Which of the statements given above are correct?

medium

With reference to the characteristics of a sound wave, consider the following statements: 1. The distance between two consecutive compressions is called the wavelength. 2. The time taken for one complete oscillation is called the frequency. 3. The SI unit of frequency is Hertz. Which of the statements given above are correct?

medium

Consider the following statements regarding Ultrasound: 1. It refers to sounds with frequencies higher than 20 kHz. 2. Ultrasound waves scatter immediately when they encounter obstacles. 3. Ultrasound is incapable of penetrating metal blocks to detect flaws. Which of the statements given above is/are correct?

easy

The cleaning action of an ultrasonic cleaner is primarily achieved through:

medium

With reference to medical applications of sound, consider the following statements: 1. Echocardiography uses ultrasonic waves to form an image of the heart. 2. Ultrasonography uses X-rays to detect stones in the gall bladder. 3. Ultrasound can be used to break kidney stones into fine grains. Which of the statements given above are correct?

medium

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Correct Option

The correct option is (a) 1 only.

Explanation

Sound is a mechanical wave that propagates through a medium. It is fundamentally a form of energy generated by the vibration of objects, which creates pressure variations in the surrounding medium.

Statement-wise Analysis

Statement 1 is Correct: Sound is a form of energy that produces the sensation of hearing. It is generated when an object vibrates and transmits energy through a medium (solid, liquid, or gas) to the receiver's ear.
Statement 2 is Incorrect: The production of sound strictly requires the utilization of energy. According to the law of conservation of energy, energy is transformed from one form to another. For instance, mechanical energy used to strike a drum or pluck a guitar string is converted into sound energy. It is impossible to produce sound without an input of energy.
Statement 3 is Incorrect: Vibration is defined as the rapid to-and-fro or back-and-forth motion of an object about a central equilibrium position. It is an oscillatory motion, not a unidirectional (one-way) motion.

Key Takeaway: Sound is a form of energy produced by the oscillatory (to-and-fro) motion of particles, known as vibration, and always requires an external energy source for its generation.